Linux

I am currently using VSCodium, which is basically VSCode built from the VSCode repo without the Microsoft bits. Somebody else has also suggested Eclipse Theia (the website pushes hard on AI because investors or something like that, but the editor itself is pretty okay. It is also compatible with the same extensions as VSCode/Codium which is pretty cool) but I've just gotten used to using VSCodium.

Of course, you have the people suggesting vim and its derivatives, which are apparently super powerful once you get used to them. Helix is another one that is kind of like Neovim but preconfigured with features that most people would want built in. I've only tried neovim once, it seems pretty cool, but I'm personally not bothered enough to go through the steep learning curve. VSCodium suits my needs just fine. If you're the kind of person who likes that sort of stuff it would be nice though. Kate (by KDE) is also a good code editor esp. if you use KDE Plasma.

One gem I found was Lite XL. It's a really lightweight editor written in Lua, super barebones, and there's a whole plugin ecosystem around it!