I'd say today my chrome-based browser (ungoogled) may load a little faster then my firefox but sometimes it's completley opposite. I don't believe the variables you describe are in general, but most likely today only? I mean IP provider traffic, sometimes antagonistic addons/extensions, global traffic, ad blockers, hardware acceeration or lack of, taxed cpu/gpu in the moment, surging processes...
...I guess I'm saying even if FF was lightning and chrome-based Brave were sluggish that this observation would have to consider a lot things at the moment.
If you are saying this is chronic daily behavior then disregard all I wrote. Spitballin and 2 cents overall.
