For website development, I would have answered Chrome until a bit ago, however I think that lately Mozilla Firefox is taking the lead in terms of usability, developer experience OOTB and politics. For example, I like how it makes data just look good, even when I directly fetch it from a REST endpoint. Chrome just displays the gibberish.
While I mainly develop with FF, I also use Chrome, because FF still has some rough edges and is missing a few tools. Lighthouse, to name one example, is still one of the best indicators what I should tune for a modern experience. Also, most people in the world use Chrome, so whatever works great on Chrome will work great on 80+% (iirc) of the world's computers. MS Edge going Chromium just pushes this number further up.
All in all, both browsers come with a similar dev experience, so you can go either way. It's a bit standardize nowadays, and even IE and Edge offer the basics (though they are not as snappy) 😉
Other than that, a cross-browser testing strategy is vital, however not something I use for day-to-day development.