This is how i initially got started and i always like to recommend it. CS50x (introduction to computer science) is their college curriculum made available for free as opencourseware. Their lectures are very engaging imo, and you get problemsets to practice and check your answers. The problems are done in an online environment which i like so you don’t get bogged down in setting up your computer before you’ve even learned how to code. And then at the end you pick a project of your own and when you finish you get a free certificate (don’t bother paying for the “verified” one)
One other thing i think cs50 does pretty well is help teach you how to solve problems and how to read documentation. The reality is that learning how to code isn’t just learning a coding language. Knowing how to solve different types of problems and how to read documentation are core skills that let you get away from “tutorial hell” and start working on a project that excites you.
So you dislike external sync options but also don’t want to pay for internal sync options? Additionally you are in a self hosted community so you’re looking for a presumably open source project (some you listed are not), and given internally supported sync services would be one way fund development i think this narrows what your are looking for by quite a bit. You basically would be looking for an open source project that meets all your other criteria and happens to let you sync the files to your own server for free. Why would such a project not just let you take things into your own hands with whatever flavor of sync/backup you prefer? Otherwise if they’re building a sync system it would probably be a monetized cloud service which brings us back to the beginning.
Maybe such a thing exists, but I haven’t seen such a thing since that is extra development for little to no gain. Most people are happy to either pay for the cloud service to fund development or sync on their own.
Logseq is open source. Obsidian is not. So yes, both have paid sync but you can also just sync or backup the files on your own. Just be careful of sync services that sync while files/db are in use to avoid conflicts.