You could just go to lemmy.world. That's your home instance, it works kinda like an email provider. And if you (for example) use gmail you can access your mail at the Gmail website and the same is true for Lemmy.
But just like you could download an email client you can get yourself an Lemy client and use that*. That client will make API requests to your home instance to get the posts it presents to you. Your home instance in turn will communicate with other instances in order to show their posts to you.**
clients/websites you could try
Here is one list and here is another. Also note that some clients are actually webapps.
* you probably know this considering you use the Lemmy client sync
** Disclaimer: the last part about how Lemmy works is just how I think it works based on what I have read. I could be completely wrong.
Yep, depending on what you do the outdated Ubuntu packages can be a real pain. I'm going to switch from Linux mint sometime soon* for that reason.
* sometime soon, aka when I finally put in the time and figure out how to install arch