To check if your problem is caused by excessive memory usage requiring constant swapping. If it is, turning swap off will make some process be killed instead of slowing the computer down.

Have you tried turning your swap off?

The answer is get a minimum linux image, add nginx or apache, and put your content on the relevant place. (Basically, your third option.)

Do not bother about the future of nginx. Changing the web server on that image is the easiest thing in the world.

There are several ways to evade NAT. Your router may or may not block those, on a case by case decision. You must know really well how it will behave to have any confidence that you are secure.

Or, in other words, NAT isn’t a security feature because it’s not built to provide security. It may be intentionally broken so your home network works better, and it may have obvious security flaws that nobody looked after. For network security, you should use something intended to give you network security.

Well, it works in a different way than NextCloud. You don’t have a server, instead you just make a share between your computers and they are all peers.

It takes some getting used to the idea, but it’s actually much simpler than NextCloud.

Yep, I’ve adapted all of my setup to syncthing, and never looked back.

Data centers get around this by:

Using network mapped disks instead of network mapped filesystems.

They use SAN and not NAS. The database and VM architecture do not fundamentally change the behavior of the disks, and there isn’t much more complicated stuff beyond that.