Hopefully this isn’t a common problem, but I was running auto bed leveling manually, the getting failed prints because I didn’t save the levelling results to the printer and I didn’t have gcode to load the levelling data and enable it in my slicer settings.
Maybe something similar is happening to you.
You can also try disabling auto leveling and level manually, that was giving me better prints for a while but it’s a pain.
Grub should be able to boot mint fine, just know where grub is installed and which disk boots the system before formatting anything. To test, unplug the windows disk and see what happens