Honestly I’m not super concerned about the contents being public.
As far as a forum/wiki, I’d like it to look like it was meant for this job, those would be a little more on the hefty side just for posting some images/text to.
I would build it myself but I’ve got a 4 month old. Not a ton of time to sit down in React.
Honestly the single biggest thing to self-hosting is breaking stuff.
Host stuff that seems interesting to you, and dick around with it. If it breaks, read the logs and try to fix. If you can’t, revert to a backup and try to reproduce.
If you start out with things that interest you, you’ll more likely stick with the hobby. From there you can move to hosting things with external access - maybe vpn inside your own network through your router?
From there, get your security in line and host a basic webserver. Something small, low attack vector, and build on it. Then expand!
Definitely recommend docker to start with - specifically docker compose. Read the documentation and mess around!
First container I would host is portainer. General web admin/management panel for containers.
Good luck :).