I like to use Kate. It doesn’t have the plethora of plugins, but it uses a fraction of the resources and has comparable built-in features.

If you want something more feature-rich with a plethora of plugins, then the IntelliJ Community Edition is under Apache-2.0. Still the corporate kind of open-source, but from a less immoral corporation.

(Neo)vim or Helix. The former for IDE.

I use VSCodium, which strips all the MS telemetry and junk from VSCode. I do find VSCode works fine as an editor, it’s relatively light on resource usage and has lots of plugins for pretty much you need. I used to use IntelliJ, but I find it’s just too much of a resource hog by comparison.

Other way around, Cursor and Windsurf have forks from VSCode into which they integrate their own AIs.

Microsoft recently made the news, because they’re making more VSCode/-ium plugins proprietary, which they do to extinguish these forks.