Thank you for being humble and describing the ways you use GitHub!
I'm the same, and it's reassuring to know that I'm not the only one just using it as a free web host for personal projects.
Until starting a new job in January 2021, I "knew git" to the extent of git pull, git add, git commit -m, and git push. For everything else I just made a copy of the repo. Now I've learned a little more about branches and merge requests, but I still make a copy of the repo and copy my changes over when things go wrong. https://xkcd.com/1597/
Like you, I got some password-related warnings on GitHub, and honestly it's scaring me away. I know it'll take an hour or so to figure out what went wrong, regenerate a ton of SSH keys for every computer I own and link them to my account, disable 2FA because my phone number is in another country... I'd rather just upload a file, thanks.
The increased overhead means I'd rather just use FTP to upload some files to an HTTP server, but I don't think that such free FTP web hosts exist any more. At least, not ones with a domain that people recognise. That said, peterburk.github.com is no longer accessible, only peterburk.github.io, so maybe it is time for me to go looking for a free .com subdomain.
I'm grateful for GitHub hosting all the junk I decide to share, and I'm obviously not their target market if I'm not paying. I just wish there were a place I could drag & drop to upload content publicly.