ubuntu makes controversial choices. Mint is explicitly user friendly, and its debian edition is like a bike with training wheels, getting you debian with extra “niceties”. LMDE (Linux mint debian edition) is, from my POV, the gold standard for noob distros. Ubuntu is explicitly like a tricycle but LMDE is like a bike with training wheels. You can eventually take them off for debian next time you change OS with less problems, if you want. I don’t think going from LMDE + Cinnamon to Debian + KDE shouldn’t be an issue.