stock firefox is decent but, depending on your goals, there are better flavors. If security is really important there is librewolf and if you care way less about security and just want awesome then floorp is pretty sweet. For me sidebery brings it all together because it lets you do things like set per container socks5, which is a game changer for me (default is all traffic through my favorite vpn provider, but I have containers to make my browser look like my local ip, American, etc.)