No, can’t be lack of anything, it was the regular Mint 21.3 installer image overwriting Debian on a normal ext4 formatted partition. Nothing should have gone wrong. Reinstalled with formatting on, and it started working.
“Hadn’t” means “had not” (not done in the past), not “had not” (lacked possession). I’m Finnish and might be wrong.
Kitchen tissue is strong when wet. Tear that square sheet in half lengthwise (because of oriented fibers), fold each half once, and you’ll have reasonably sized pieces.