Before you mess with commands I suggest you to do what I mentioned before. The picture you sent has the grub bootloader and assuming windows didn’t nuke it, when you choose your Linux drive to boot first it should come back.
Also changing the boot order will not break your pc
You entered the boot selection, which is used for quickly booting into a different drive but it doesn’t change which drive the PC boots into by default. To change that you’ll need to enter the bios proper and you do that by spamming f2 or delete key just like you did with the f12 key.