Duplicated and repeating text input in macOS Catalina

After upgrading to Catalina, I’ve been struck by a very strange issue: When typing and using the keyboard in general (either the built-in keyboard or an external) it will randomly duplicate some of the input, so that I’ll need to go back and edit the jumbled text constantly.

While trying to write “Maybe it” just now, I got "Maybe iMaybe t”, in addition to more examples like it. I can’t for the life of me figure this one out, and I’ve found a couple of other threads from people having the same issue (it does not seem widespread):

Double typing text on Catalina?

Duplicate keyboard input after upgrading to macOS C Catalina

Any help?