Hi livthomas, and welcome to the forum.
We have this long thread on the topic of Laggy scrolling.
In that thread, I posted this note with a number of troubleshooting steps you might try.
The TL;DR version:
Yes, this is a known bug with Scrivener version 3.3.6 and macOS 14.5 Sonoma.
It seems to occur most often if a user’s project uses Page View and/or has a large document and/or Scrivenings session loaded. Also, the Mac’s built-in trackpad seems to be more likely to have the lagging issues than an external mouse with a track wheel.
In some of the help tickets, a few users reported improvement in the lagging if they went to Scrivener > Settings > Appearance > Main Editor > Options and enabled the “Highlight current line” command.
This seems most useful for those working in Page View.
If the box that’s added from that command is annoying, you can go to Scrivener > Settings > Appearance > General Interface > Options and untick the “Draw border around current line highlights” to see if that improves the behavior.