I just did the proces from PC to Switch, what I do was the following:
1- Entered to C:\Users\USERNAME\AppData\Local\Phoenix\Saved\SaveGames\NUMBER FOLDER\
2- I edit all the files, deleting the .sav, as mentioned up in this post.
3- On Switch I back up the save.
4- On PC, entered to your Switch SD Card\JKSV\Hogwarts Legacy\BACK UP WE JUST CREATED
5- Copy all the files you rename without .sav
6- On Switch, go to JKSV, and restore the folder where you put the files (should be the same name with the date)
7-Enjoy your game with the progress sync.
I haven't tried to transfer the save from Switch to PC, but I guess is the same process, just copy the back up you created with JKSV on Switch and then add the .sav to all the files, then put it in C:\Users\USERNAME\AppData\Local\Phoenix\Saved\SaveGames\NUMBER FOLDER\
Hope somebody helps it!