So i am planning to create a server to run a few different services.
That would be:

• Apache
• vBulletin
• MediaWiki
• An IRC Server
• An IRC Bot
• Maybe one or two php scripts (once I know what that is) - essentially being forms that turn the input into an HTML Character sheet.
• The dependencies (php + MySQL)

I don't plan on installing SSH, as with my life, as it looks like, will likely never put me in a position where I would have to or be able to remotely access the server and couldn't wait the, at worst, 8ish hours til I get home to fix it.

There are however a bunch of things I am unsure about/still have trouble with:

When installing Ubuntu Server, I can set a Nameserver and search domains - I do think I know what they do, but do I need to set them on a server ? I am fine with using just whichever for now and don't need a particular one.

What advantages does Docker have ? I do understand that it separates programs from each other like a VM would, without the need to have separate OSes, but do I really need that for a web server ?

I am looking for a time-machine like back-up solution for this server. As in, I plug in a hard drive, hit back up and should the server ever die, I just pull it out, plug it into the new one and hit recover, bringing the server back from the dead as if nothing ever happened.
Now I've researched this a bit already and it seems like this would require two solutions as Timeshift, the most popular option, backs up the system, but not the userdata or the other way around and to get what time-machine does you essentially need a certain file system and two softwares and it's by far not as simple as Time-Machine.
Is there an easy way to solve this?

Which does however also bring me to my last question.
Couldn't I just use MacOS for the server ?
APache, MySQL and php all do have MacOS versions and even if they did not, I could still just set up a VM on the Mac and get all the advantages from Time Machine, allowing me to back up and recover my server without much trouble.
And a Mac mini (M1, 8Cores, 8GB of Ram, 256GB Storage) is 400 bucks refurbished. Twice as much as I wanted to spend, but it also has twice as many cores as the S100 I was initially eyeing and comes with a build in remote access solution. And I think for the tasks at hand, it's more than enough power. Not only that but other than the S100 I could also use it for other tasks should I ever decide that the project isn't worth it anymore.

Edit: When installed on the VM the Webserver is meant to be only accessible from within the Network to allow me to set up forum and wiki before going online. Once transferred to the physical machine, it’s meant to be accessible from the outside.