I'm glad you asked.
Firstly, Molly's Game-Save M.U.L.E. is clearly the prettiest.
Secondly, other programs I've seen will determine the file with the most progress by considering only the most recent file write.
This could potentially cause a file with less progress (if opened most recently) to overwrite a file with more progress.
Click here to download the installer.
Program will be found in the Start Menu or via the desktop shortcut created by the installer.
For the smoothest experience, make sure Deep Rock Galactic is installed on both Steam and Game Pass, and that each version of the game has been launched at least once prior to launching Molly's Game-Save M.U.L.E.
This will ensure that both save files have been created; both must be present to initiate the transfer.
Click Sync Most Progress to let Molly figure out which file has the most progress.
You'll see a message detailing which file (Steam or Xbox) has been chosen and why.
Click Yes and your progress will be automatically transferred to the other platform!
Select Steam to Xbox OR Xbox to Steam
Click Yes and your progress will be automatically transferred!
Click Set Folders, click the Steam or Xbox tab, and click the Choose Save Folder option.
Select the folder that contains your save file.
Your settings are saved!
Molly's Game-Save Mule has buttons to immediately open the folder(s) containing your save files and highlight the correct one.
In case there's an issue with your save folders, here are the default save file locations:
C:\Program Files (x86)\Steam\steamapps\common\Deep Rock Galactic\FSD\Saved\SaveGames
C:\Users\your username here\AppData\Local\Packages\CoffeeStainStudios.DeepRockGalactic_random numbers and letters here\SystemAppData\wgs\long string of random numbers and letters here with an underscore somewhere\another long string of random numbers and letters here
There are two files in this folder; the one that's named with random numbers and letters is the save file.