What does it even mean to be all-in on a browser? You can switch any time, multiple times per day even.
No, not if you are "all in" and spend enough time customizing it or getting used to the UI/features uniquely available to a specific browser. You won't be able to switch multiple times a day without noticing a lot of friction as you common workflows break down
When I was a developer, I fell into the trap of trying to customize everything, only to have to keep doing it once a new browser or extension came out. I gave up trying to get something exactly the way I wanted it.
I use as close to stock as possible in order to avoid the kind of friction you're talking about.