Chromium is the best browser to use on Fedora for several reasons. Most notably, it is zippier than Firefox and Vivaldi.
Install Chromium
sudo dnf install chromium -y
Enable Video Formats (H.264)
Install the following libraries to get H.264 and other video formats to render correctly. This will make YouTube and other video sites work flawlessly.
sudo dnf install chromium-libs-media-freeworld
Why I Switched
I switched to Chromium after being a Firefox user for a long time. Right before the transition, I was actually bouncing back and forth between Vivaldi and Firefox.
Firefox would turn sluggish after reaching a certain number of tabs. At one point, it wouldn't even clear the cache when the development tools were open.
Vivaldi had its own issues. It would lag and struggle to render pages, and the default animations felt noticeably slow once I had more than eight tabs open.