The Samsung Galaxy XCover6 Pro has a replaceble battery while being IP68 dust/water resistant, which means it can be submerged in water up to 1.5m/5ft for 35 min. It’s definitely possible, but they just don’t want to make such phones apparently.
‘Normal’ Mint is still based on Ubuntu, but there is LMDE (Linux Mint Debian Edition), which is Debian based.
No, public like owned by investors who bought stock and want profits.