I'm meaning in terms of appearance, and especially customizing shortcuts. I already use Firefox customized mostly to my liking, but I don't like having the same

I'm meaning in terms of appearance, and especially customizing shortcuts. I already use Firefox customized mostly to my liking, but I don't like having the same generic (very tall) top bar that everyone gets. Tab management leaves some to be desired compared to Vivaldi. Yes, there are extensions for that, but they don't function as sleek.