That's one reason I was very much a fan of the old "It's All Text" extension for Firefox, which let you open any text-box in an external editor.

Sadly, it's not going to make the transition to a WebExtension. There are other WebExtensions that do something similar, but they all start with "install node and this sprawling mass of dependencies", so I said "no thank you".

Someday I'll write the equivalent as a standalone, statically-linked Rust binary... but not today.