NAS, Home Servers, and where do I even start?

I’m having trouble finding a proper starting point for self hosting, so I am curious on any resources you’d recommend, or even some build lists / pre-built devices.

What I want to do:

Important

Host some applications like TinyTinyRSS, Jellyfin, GitLab, and Nextcloud which I’d want to be accessible in my home network
Use the computer as a NAS to back data up and have it easily accessible on my desktop and laptop
Have a piHole

Optional

Access my hosted applications from outside of my network
Use tools like Radarr to automatically download things from torrent lists
Use it as a seedbox

The reason the last three are optional is because for that I’d have to expose the computer to the outside network, which has a whole bunch of benefits, but also a whole bunch of risks I am likely neither capable of nor comfortable with working around, so unless there’s an easy fix (number 3 might be able to be handled via a VPN?) they’re a problem for future me. For anything further I think I can just go from here once those requirements develop

I have already skimmed through some articles, watched some build guides for both NAS and home servers and honestly I just don’t know what I need, both in information, hardware, and software.

Should I separate the NAS and Home Server, get a separate device for the piHole, or just have all three in one?
What hardware would be suitable for this?
Should I buy something off the shelf like a mini PC (for instance an Intel NUC) or one of these fancy prebuilt NAS devices where you just need to plug in some drives or build my own?
Would it be smarter to go with a Linux distro as the OS, for instance Debian, or should I use something like Unraid or TrueNAS which from what I can gather make setup more convenient and even handle docker images for you?

I am somewhat comfortable with Linux and the command line and have a budget of about 1000€, but if I can get away with less that would be great, and I can also stretch higher if needed for my requirements. I am also very new to self hosting and my networking knowledge is not non-existent, but limited.

I’m just a bit lost and would love some beginner-oriented resources or direct advice, thank you!