To understand networking: read a book. Much of my early networking knowledge came from https://dl.acm.org/doi/book/10.5555/1593414 but you can probably find more modern variants of such a book. Getting a good grasp of networking requires reading and experimentation; luckily, you've got the tools for experimentation already.

Most of application deployment is little more than reading the docs and tuning the configuration to your needs. From what I read, I think you've got enough knowledge to get that stuff running on your servers. You can probably get a lot more out of learning about the underlying concepts.

For your own photos and cloud: I use Seafile, have used Nextcloud, and alternatives exist. Quite easy to set up, but with the ability to go deep into Modern (TM) Cloud (C) backends if you want.

For your Bitwarden setup: Vaultwarden is a lot easier on resources and has pretty much all the features you need. Also quite easy to set up.

For your tailscale setup: there's a guide for the server (https://github.com/juanfont/headscale/blob/main/docs/running...) and you can find more guides for the clients.

For your Git setup: Git works over simple SSH. If you can SSH into your server, you can host a git repository. If you want more (a nice web GUI) then Gitea or Gitlab can also be run on your server.

Things I recommend reading into if your knowledge about them is spotty (find guides or book recommendations):

- Networking (ARP, IPv4, IPv6, TCP, UDP, DNS, mDNS, maybe PPPoE, and other such abbreviations). This is a lot of reading. You can also try to get started with this stuff without reading into it (it's how I learned!) and have a terribly frustrated time by overlooking obvious mistakes and easy solutions, but I don't recommend that.

- SystemD services. People use Docker to solve a lot of daemon problems but good ol' systemd can do a huge part of that! I run most of my services in systemd rather than some kind of container setup because I don't want to have to deal with Docker and its many friends and dependencies whenever I'm trying to resolve a problem and so far it works great.

- Reverse proxies, if you're running multiple services on a single server with subdomains or subpaths; learn about nginx/caddy/apache2/whatever server you prefer and how to set up proxying. Along the way you will break stuff and learn new things with every error message or unexpected routing error you encounter!

- Firewalls; firewalld and ufw are nice ways to get started, nftables/iptables for the underlying stuff. It's not hard, per se, but it can get complicated fast. Maybe mess with the Windows firewall as well just for fun.

- Set up IPv6 if you don't have it already. This would allow you to do some more networking stuff and prepare you better for the future, because corporate networking people seem to be grumpy and annoyed at the thought of one day needing to enable a protocol from the 90s. If your ISP only does IPv4, https://ipv6.he.net/ will get you an IPv6 subnet for free and if you do all of their quizzes they'll even send you a free shirt!

- Along the way, you will (or should, at least) learn to use Wireshark and friends. Incredibly overwhelming at first but with some knowledge about networks you'll get the hang of it by setting up the right filters.