I have super light office requirements these days and those are satisfied with OnlyOffice (https://www.onlyoffice.com/). I do believe it's an Electron app but works quite fast in my personal experience. (Probably faster than LibreOffice if it's still like the last time I used it).

It's open source: https://github.com/ONLYOFFICE/

I hadn't looked at the Github page in a while. They seem to have a ton of new features one of which regrettably is a very front end center AI presence.

I've been using it on my phone for the occasional document and its been quite nice, much quicker/accurate than collabora office