Uninstalled Steam, then applications would not launch and bootloader disappeared

[hui]

@petran79

Could deleting the .steam folder have deleted the whole system?

@petran79

Could Steam have messed the system to such an extent?

Answer: No and no.

@petran79

Tried to install a game, unfortunately Steam could not recognize the external HDD, only the home folder.

Quite common issue with easy solution:

Steam does not write games onto NVME

Steam requires the FULL PATH (base directory) to be owned by the user who runs Steam. This is reported on several threads and forums around the net. This can also be seen by monitoring the terminal output of Steam when trying to download a game. That means /home/youruser/steamdatadirectory/ → works, as the complete home directory is owned by the user /mnt/steamdatadirectory/ → don’t work as /mnt is owned by root /steamdatadirectory/ → will work if this directory is owned by the user …

@petran79

Then to my surprise, no Grub boot loader anymore and Windows 10 booted instead!

As you fiddled around with your system, adding and removing drives, it is quite possible that you simply need to check the UEFI boot order in your Bios and point it to the Tumbleweed OS/partition/drive.