towerful

Proxmox is a great place to start. It has a nice web ui, it's easy to install, and has loads of useful features for running VMs.
You can easily run windows or whatever Linux VMs you want.

Before spending big money on a beefy server that may or may-not do what you want, I'd suggest buying a cheap NUC (intel N100 nucs are cheap, and have an iGPU).
Then you can follow one of the many tutorials out there about Proxmox, Windows and GPU pass through.
Once you have a windows VM working, you can play around with remote desktop stuff, and see if it is responsive/suitable - things like Apache Guacamole or Rust Desk can make for a very nice end user experience with a bit of extra upfront config.

If remote desktop stuff isn't working for you, you could try buying some used Crestron NVX from eBay. Can't remember the exact model, but they are about £160.
They have very little latency, but they will saturate 1gbe so need a home-run to the same switch (or 10gbps+ trunk links between switches).

Once all that is feeling good, think about other services you want and get them running on the (starting to get overloaded) n100 nuc.

When you have everything feeling good, then you can invest in a beefy machine with all the bells and whistles.
Considering the n100 is for learning, with the idea of rebuilding the entire server: document what you do!
There will be lots of trial and error along the way, and you will mess things up. So make sure you take lots of notes about what you do to configure things, and take snapshots of VMs before you start tinkering with them.

Uh, don't?
You want a Lemmy instance - that I presume you would want to be somewhat reliable - without doing anything? WiFi prioritises convenience over speed and reliability. So, things will randomly fail.

I guess pay for a Lemmy instance provider. Probably the easiest. But this is self hosting, and it sounds like you want a place to start and have chosen "hosting a Lemmy instance" as your learning ground.

Something like cloudflare tunnel will let you punch through a firewall without having to mess with network stuff.
A docker compose stack makes things as easy as they can be in such scenarios.
These are terms you can google "Lemmy docker compose cloudflare tunnel"

Here is 1 result: https://lemmy.world/post/299429

Here is a GitHub for Lemmy in docker compose https://github.com/Drakeyves/lemmy-docker-setup

This looks like it covers cloud flare in a compose stack: https://joelparkinson.me/self-hosting-with-cloudflare-tunnels-docker-compose/

Read through, learn docker compose, understand cloudflare & cloudflare tunnels

Wouldn't it be better to have highly available storage for the git repo?
Something like Ceph, Minio, Seaweedfs, GarageFS etc.
Cause git is file system based.

Censoring*

Censure is like a harsh criticism

SystemWaylandD

What a stable government

my router and my reverse proxy (traefik) is able to receive the necessary SSL/TLS certificates however

From something like LetsEncrypt?
As an HTTP-01 Challenge? Not an DNS-01 challenge?
Http challenge means that port 80 is accessible from the public internet (because that's how LE can confirm it can reach your server via the public DNS records, proof of server ownership).
DNS-01 is about proof of DNS record ownership, and doesn't prove public internet access.

Also, what are you self hosting?
Does it really need to be publicly accessible? Or just accessible by you and people you trust?

If it adds to the content, then it is worth something. So make someone worth something.
If it doesn't matter, add a random screenshot of kernel code.

The "worth something" doesn't even have to be financial.
Find a nice image that someone has made which is linux-related, and ask if you can use it & credit the author.
If no, try someone else.

If that's too much work, use a random screenshot of kernel code ...

There are artists out there that have already freely shared some really cool art, that would love to be able to point to publications that they have permitted to use it.
If you have some budget, pay them. Value the time involved.

Just not AI filler BS. I'm not going to see some filler AI art and go "oh yeh, I'm going to use that for X/Y/Z".
But if I see some cool art, I'm inclined to commission something for an actual use case

I swear, if it didn't have a $ in it, it wouldn't have had the initial 18 rating and yt wouldn't be restricting it.

It could've been cookies, and I bet it wouldn't have faced the pushback it has.

It's a rogue-lite. It just happens to be played with cards and poker hands. But the only gamble is Wheel of Fortune, and that isn't a gamble cause it never hits

Sounds like you have had a very productive life! Your son is very lucky.

Encourage the education. But there are loads of good careers that don't need university degrees.
And all the while, he can try and achieve his dream.

From personal experience, university wasn't useful for me - other than giving me time to figure out what I don't want to do, and meeting friends that are still friends to this day.
But I could've easily done an apprenticeship, or gone straight into some industry/company. Some days, I wish I had. Other days, I wouldn't want to be doing anything other than what I am atm.

Dream case, he makes it.
Best case, he figures out what he wants to do by 21.
Worst case, he's still figuring it out when he's 25.

I wasn't making decent money until I was late 20s. Even now, I can't guarantee I have enough work next year. It's extremely likely, but I'm self employed so...
Knowing my folks will still support me means I can continue pursuing interesting, useful and innovative things, even in my 30s - even tho the support is no longer required.

Maybe talk to some of your contacts in the football industry.
See if they have similar "football or nothing", or if they had backup plans.
Talk to some managers, coaches, sports scientists, medics etc.
Ask them how they would get into pro football. Ask them what happens to pro-football aspiring players that don't make the cut.
Use your experience and connections to help and support your son. And be there if it doesn't work out.
You might know better, but he still has to learn. The best lessons are mistakes.

Did you go straight into being a pro footballer? Or did you have back up plans? Like "if this doesn't work out, I'll be an electrician" or something?

I've never had super lofty goals, but my parents always supported me in what I wanted to do. They never tried to steer me, but they did ask pertinent questions about what I was planning at various points. Probably to hint at bad idea.
I feel like I could have asked them for money/support at any point for any of my projects/ideas/whatevers, and - after making sure I was serious - would have helped out however they could.
I have a very unique career at this point, and I am only in this position because of the eclectic experience I have. And it is completely unrelated to my dreams as a kid or what I studied at university.

Ultimately, he is growing up. He's going to have to make mistakes.
I'd say you have to be prepared to support him as much as you can in his dream of being a pro footballer.
Maybe he won't be a pro footballer, but he might get a satisfying career out of being football-adjacent. Medic, science, coaching.
Or maybe he will try it for 5 years and eventually realise it's not gonna happen, and be an electrician.
Or maybe he will struggle for 2 years, realise he needs to double down, and make the cut a year later.

I had a friend when I was growing up that dreamed of being an RAF pilot. Everything he did was around that.
Due to some unfortunate life circumstances, that dream was ripped away in the space of a week. Completely out of anyone's control, but he could no longer qualify as an RAF pilot.
He was heartbroken. He's now an engineer/mechanic in the RAF and loves tinkering with cars.

He shouldn't find another dream.
But he should be aware that dreams don't always come about. And if this dream doesn't, would he be happy in an adjacent career? Or something else entirely?
Help him research the backup plan.

I moved to endeavouros. First time using a rolling release, and I was struggling with some webdev stuff cause node was on a recent non-lts build and a few other things.
Not a problem for building, cause I already have that containerised. But things like installing packages was refusing, and obviously couldn't run dev workflows.

Until I realised I should just work inside a container.

I know vscode is still Microsoft (and I'm sure I could get it to work with vscodium), but the dev container workflow is fantastic.
Absolute game changer.
And I know I can easily work on a different platform, os whatever. And still have the same dev environment.