ZFS ZIL will not help in this case.
TheHolm
Usually it can be solved by talking to hotel stuff. you are paying for that service and can expect it be suitable for any legal use.
Nope. You do not need physical access for it, just root access. and you HW is compromised with only means to recover it is SPI flashing of CPU.
3600 was released in 2019. And it they was making it for at least 2 years.
You need to be a root to exploit it, but if it get exploited any way to get rid of it is to throw MB to trash.
Why use SSD OS (unless he is using windows ). System can do to USB stick and rest od data to disk, and SSD may be a good option.
Does not really matter what wording they will put in. It is clear that project will go to pay or get nothing way. So just start working on decommissioning it. Free software really need better ways to pay developers, that will allow to avoid crap like that.
I would add LVM to the list of software raids, and remove btrfs as poorly engineered.
couple of old 2.5 HDD + usb to SATA converter. But Pi5 is hardly suitable to host anything. May just get old PC (which gives you HDD too). There are plenty for < $100 or even free. But you are going to pay more for power.
I do not see why it will cause any problems with exception of stacking mapping layer. I wonder can LVM do it natively without adding intermediate block device of 2 x 2G?
Stay with TP-Link. Ubiquity done some strange things recently.
LE only certify your domain name, you may want to put more (like company name) to cert and it is where classic certs providers come to help.