I’ve been doing Linux server administration for 20 years now. You’ll always have to duckduckgo things. You’ll never keep it all in your head, even just a single server with a handful of services. Docker and containers really isn’t too hard. Just start small and build from there. If you can learn how the chroot command works, you’ve pretty much learned docker. It’s just chroot with more features.
Yacy is pretty great.
I would honestly recommend buying an old laptop with a broken screen (or an old netbook or something, make sure it has an Ethernet port), a decent DSL modem, a USB network adapter, and a switch if you need it. Now you’ve got everything you need to make a super capable router. Install a very basic Linux distribution and get NAT setup (it’s like 4 or 5 commands), configure the firewall, and your VPN software of choice. I’ve run a setup like this for years and it’s great, because any time a component is “out-of-date” you just update that component. For example, you need AX WiFi instead of AC, just upgrade the WiFi adapter).
I had a section in university on binary exploitation. It was super fun. We got to do some buffer overflow attacks, dynamic linker exploits, and command injection. Reverse engineering is super frustrating for me, but very rewarding when you finally get it figured out. I admire those who can do it well.
I came back to Gentoo after years of Kubuntu. Once they forced snap down our throats and started pulling other weird crap I knew it was time to make a change. I came back to Gentoo and it’s been pretty great. Still a few things to iron out on my laptop installs, but it’s great for my home server.