If you follow the 4K/HDR instructions in the wiki and run the GUI at 1080p so Kodi only switches to 4K for playback, and use a remote device that scrolls well, the overall user experience is very fluid. Use of pass-through audio for Atmos has no relevance to anything being “fast” in my (daily driving an RPi5 since before launch) experience.
Thank you.
If you don't mind, could you link the "4K/HDR instructions in the wiki and run the GUI at 1080p"?