Machine wise anything will work. Give yourself a chassis with room to add more disks down the road or just build your storage setup in a way that gives you what flexibility you need (though that tends to come with sacrifices).
I use Nextcloud for general file syncing between devices as occaisonal small file sharing.
Mulvad is great but if you need port forwarding you'll have to look elsewhere as they no longer provide that feature.
I use keepass2android and "sync" via its native WebDAV support with my nextcloud instance as the source. Been working great forever.
Ah, well, then perhaps I will monitor it.
For internal use I just monitor everything with zabbix. What Ive been wanting is (as I said) a public "status screen" that my few users can hit just to verify if things are in fact down or if it's just them.
Ok, you might have finally gotten me to consider a "dashboard". I've been wanting a simple public facing service status page and this sounds like a nice solution.
Haha, I've never had to deal with something quite that high pressure but I've definitely been a little looser than standard during at least a couple emergencies.
Kernel upgrade WHILE you're out for beers!
Someone just posted their own short reviews of a slew of wiki options in this community so maybe go take a peek at that.
Personally I'm finding I like Otterwiki quite a lot though I've not yet dug deep into it.
As someone with no such mental barriers you'll have to take take my words with a grain if salt. I'm certainly not ever looking to make purchase something that is crap/doesn't work/is useless. I do as much research as i can on the item, think about how I expect to use the item, and try to think about what may work and not work about the time.
If I can't come up with a strong objective reason to not get it then I buy it. Generally you can return most things so if I'm particularly hesitant about something due to too many unknowns I'll just make sure I can return it. Sometimes there may be a few but I consider that the price of the lesson.
There is also nothing wrong with asking the opinions of others if you know nothing about it and you know someone who might. People ask me about computer and electronics purchases because I have a lot if experience and can typically advise them of things they didn't consider.
What I don't do is ask people who know little to nothing about whatever the item is and then base my own opinion entirely on their uneducated one.
At the end of the day though you really just have to allow yourself to make mistakes. There's nothing wrong with that and is often the one if the best ways to learn something.
I use portainer extensively and am quite fond of it. I normally live on the CLI so picking a GUI tool over cli management is unusual for me but I've found portainer largely just makes typical management easier and doesn't get in my way at all.
For your other questions I have no answers. I self host everything so to me "what is worth running" is not a question that makes sense. I run what I need and my needs therefore define what I run.
I stick to IRC over matrix.
500Mbps isn't a measurement of electrical consumption
Check out the Teamspeak6 beta. I don't know about offline messages but it addresses all your other complaints. I moved to it from Mumble somewhat recently and have been very happy with it.