I noticed that after installing some games from SideQuest, the Files app in Oculus would show tons of files that it found as media in those game folders. I speculate that the media scanner going on in the background is overloading the system at times trying to categorize these files, likely for no reason.
A fix is to drop a .nomedia file into the root of the game files folders. This file has no content and is 0 bytes, and you can take the one found in the sdcard/Android/data or sdcard/Android/obb folder and copy/paste it where needed. This file is hidden by-default on Linux through most GUI file explorers, but I'm not sure about Windows and Explorer, or if the file is shown in SideQuest.
sdcard is the root folder you're in when browsing the Quest 2's internal storage from a computer (via file explorer or SideQuest).
To see if you're potentially affected: Open the Files app. If you have tons of media there that isn't expected and you've installed things from "Unknown Sources" (sideloaded apks, SideQuest), you're running into this.
To see if this is fixed after pasting .nomedia around: Open the Files app. Media from any video recordings or screenshots you've taken from the official Oculus UI, or manually copied over to expected folders (like full movies to the Movies folder) should only be shown. If some unexpected media is still being shown, try rebooting.
I just factory-reset my Quest today, so I can't quite tell if this would have solved my issues or not. I noticed my new 128GB Quest 2 was more laggy than I cared for at times, notably when in the home screen. The worse was when I was trying to use Immersed. I factory reset and immediately did the .nomedia files when restoring my game data, and everything is still pretty snappy.
At the very least, if this doesn't fix random stuttering/lag, it will make the Files app actually usable if you've installed games/apps outside the Oculus store 😛