What do you look for in a Code Editor?

I find myself often searching for better editor experiences when writing code.

Things I've tried:

• Visual Studio code: too slow, resource hog.
• Atom: same as above.
• Intellij: very slow to open.
• NeoVim/Vim: steep learning curve and requires a good memory (human, not computer!).
• Lite (and Lite-xl): lacking fully-featured language support currently.
• Sublime Text: Has probably come the closest to my reliable editor, but actually getting it setup to be an editor can be fiddly, because it's primarily supposed to be a text editor.

Things I need:

• Speed - my biggest frustration
• cross-platform
• LSP integrations (specifically gopls and pylsp)
• debug support (delve, pdb)
• Large extension library / list of plugins

Things I want:

• Nice Testing & coverage visualisations
• Kubernetes & docker support
• hackability / customisation

This got me thinking, with modern LSPs (Language Server Protocols) and rich web-based ecosystems - what do you look for in an editor?