General Help and Suggestions

Hi friends, brand spanking new here and I wish I'd found you all much earlier! I'm looking for general best practices for self hosting Minecraft servers. I see a bunch of threads I'm reading through that answer my questions one at a time, but I'm hoping for some general pointers here or links to more specific threads. Prepare for background info you can skip if uninterested by looking for the bulleted questions 🙂

I've been casually hosting MC servers for years but decided to up my game last spring. Went through lots of iterations of ideas that aren't helpful even as background 😄 Anyway, I started out by tinkering with AMP on a spare PC. That seemed alright, but at the time it didn't play well with security stuff so I moved on. I tinkered with Pterodactyl, but before committing to that I found GSA. While paid, GSA made the container part of hosting easy, automated playtime rewards with a community currency "store", and it made hosting a few other games I was interested in a basically turnkey thing. I tinkered with monetization for the servers, but started into that enterprise with a less than reliable crew. That brings me to today.

At this point I plan to host pretty much just Minecraft with the occasional side server for me and a few friends. I'd like to give monetization another shot if I can bring the server up to that level of quality, and I am very familiar with the restrictions on that from MS/Mojang. I have two heavy duty servers (top end consumer hardware, not commercial stuff), solid fiber internet, and would like to do this out of my home as a light side-gig with a buddy who doesn't know there are games that aren't MC. So, to questions.

Please answer as though I am a new admin where reasonably possible, most of what I know has come "on the job" and I likely missed obvious things. Based on questions I've read here, here are things I know I need to know more about, other thoughts are welcome as well.

1 - I am quite confident my network security is not sufficient. While my current service (GSA) automates ports, containers, and firewall stuff on the PC itself, the connection address is still my home network public IP. I saw some good articles here with specific questions, but is there a thread or link that would teach me what I need to correct my terrible network security in general?

2 - I don't love that GSA is paid on top of my other expenses, but it is automating several things I would need to split out otherwise, and I get the feeling from reading posts here there are better alternatives. What are the community favorites for the following tasks:
a - Hosting modded Java MC servers.
b - Automating security for the servers as much as possible. It sounds like Pterodactyl would take care of "a" and most of "b" at the same time?
c - Hosting a community website. I have been hosting home based servers and tinkered with modding before, but not with anything web related. Without learning web development, I would love to have tools for linking to community resources, posting stories, and integrating a web store. The store doesn't have to be built into the site, we'll get to that in a second.
d - Running a web store. This needs to support real world payments and run commands in the server(s) automatically. I'm leaning towards Tebex but there seem to be alternatives I know little about. Also to be fair, GSA makes this really easy as the community currency can be earned through playtime and works across any number of MC instances.
e - Pie in the sky here, is there a panel that can update either a mod pack or set of mods, while of course choosing one or the other to avoid messing up a premade pack, either automatically or when prompted?

3 - Minor thing, if it even really maters is there a community favorite resource for picking up domains?

4 - Possibly out of scope or too generic of a question, but are there services I can add through my domain that add value to me or my community on my home servers?