I know I could and should encrypt whole drives but I want another layer of protect specific folders when my devices are unlocked, a password. I want the folders to behave like regular folders where I can add or remove files as usual, without a clunky UX like password protected zips. I looked it up and didn’t find any straightforward solutions.
You can use 7zip to archive files into a .7z and protect it with a password. 7zip is cross-platform, it’s available for Windows, Mac and Linux.
Edit: sorry, I see you have already evaluated this option. I don’t know another method that would me more transparent.
That is massively insecure