If you’re having slow and jerky scrolling in Firefox with Gnome 3, this is worth a try, especially if your Chrome scrolling is fine.
1 Open firefox.
2 Type about:config in the Firefox address bar and hit Enter.
3 Type mousewheel.min_line_scroll_amount into the search bar.
4 Double click the row that shows up, enter a higher number (I use 30) and press Enter.
You may have to tinker with the mousewheel.min_line_scroll_amount to get the behavior you want but hopefully this resolves your problem. Thanks to the folks on this reddit thread for the answer.
My environment is CentOS 7 and Firefox 60, but this problem seems to be generally related to recent (e.g. ~2018) Firefox on recent Gnome.