DNS is what you’re looking for. To keep it simple and in one place (your adguard instance), you can add local dns entries under Filters > DNS Rewrites in the format below:
192.xxx.x.47 plex.yourdomain.xyz
192.xxx.x.53 snapdrop.yourdomain.xyz
What is your root filesystem installed on - lvm, zfs, or bare disk partitions? Are you booting with grub (legacy/bios) or systemd-boot (uefi)?
If you can find a cheap used micro-form-factor pc with hdmi output (eg thinkcentre m93p), that’s a great sustainable way to go. Stick debian on it, get a cheap tiny bluetooth keyboard/trackpad, stream via web browser. Bonus if it’s got a dvd player, for the ultimate utilitarian foss htpc.
For donating compute/storage/bandwidth to community archiving, this is a great place to check out: https://wiki.archiveteam.org/
Just my opinion, but I think they’re a great project to support.
Forgejo, a Gitea fork used by Codeberg. I chose it because it’s got the right balance of features to weight for my small use case, it has FOSS spirit, and it’s got a lovely package maintainer for FreeBSD that makes deployment and maintenance easy peasy (thanks Stefan <3).