The first thing you need to do is disable steam save synchronization
Open steam > select Deep Rock Galactic > select the gear on the main menu > Properties > remove the slider from "Enable synchronization of saves with Steam"
Open the game save path, by default this is (C:\Program Files (x86)\Steam\steamapps\common\Deep Rock Galactic\FSD\Saved\SaveGames)
Rename the downloaded file 76561198201230350_Backup_2.sav by rewriting the numbers in the name to your Steam ID. To do this, you need to rename the file so that the numbers match the files in the folder, for example 76561198201254354_Backup_2.sav
Delete the original Backup_2 and replace it with the renamed new one.
Let's go into the game.
Open the menu, go to settings > save menu > restore save > select Backup 2 save.
If the save says that the player's rank is 633, then you did everything correctly
Loading the save and overwriting progress
After the save has been overwritten, you can turn back the synchronization of Steam saves