Raw files are automatically processed by Samsung's Gear 360 ActionDirector Windows app. These processed files have the word "_Stitch_" in the filenames. These stitched files seem to work in Meta Quest 2's TV app, after direct transfer from PC to Quest via USB-C to USB-C. However, a lot of these files do not work right away. It seems to take time to "process" by the Quest app.
The ActionDirector Windows app also has the menu feature called "produce" to produce 360 video, which apparently should be different than the automatically processed "_Stitch_" files. These produced files work right away after uploading onto Youtube while the _Stitch_ files do not work as 360 from direct Youtube upload.