I will probably get flogged by this answer but here it goes:
I'd throw you right into the deep end: get a spare machine (an old laptop or PC) and install proxmox on it. Play around, breaks shit, delete the container/VM and start over.
Grab stuff from the Community Helper Scripts and see new stuff, try alternatives, see what works for you and don't be afraid of breaking stuff.
It takes a bit longer and some basic concepts might fly over your head, but the stuff you learn like this, you learn by heart.
It's been a few years since I started tinkering with a laptop with a busted video output circuit. Now I serve NextCloud and Immich to my family, keep receipts and documents neatly organised on Paperless, have a decent arr stack and a bunch of extra goodies. All from "a PC without video? Might as well make a server" now with a proper machine with several drives on ZFS pools, health checks and redundancy.
Its a helluva rabbit hole.
Good luck!