If you wanna tighten up your extension build process feel free to steal my build setup :) (https://github.com/Baizey/UniversalAutomaticCurrencyConverter )
It's using esbuild and I'm using it to bundle for both chrome and Firefox separately (they expect slightly different manifest files), has multi entry points support (background, content, options and popup) and builds for ts/js
Oh yeah, but the current manifest v3 difference between Firefox and Chrome is peanuts compared to when I had to have custom logic around regex as they didn't support the same set of regex specs. Fuck that