I have primarily been using Chrome up until this point as I was under the impression that performance (and therefore battery life) is bad with FF on MacOS. Recent results seem to indicate that Chrome is in fact the worst offender [1].
Yesterday I uninstalled Arc as they have all but abandoned their browser to work on some AI crap browser (after saying they planned to support manifest v2 for the forseeable future).
Today I installed Orion Browser [2]. It's using webkit under the hood and seems to be far lighter on battery life than Chrome, Arc (Blink) and Firefox. They fully support FF and Chrome extensions and therefore UBO seems to be working (on the whole) very well.
[1] https://birchtree.me/blog/everyone-says-chrome-devastates-ma...