I’m not so sure it’s actually okay for manufactures to say using aftermarket parts voids the warranty - they need to prove it’s actually your fault the device is broken (America’s Magnuson–Moss Warranty Act). If you’ve seen those little stickers over screws that say “warranty void if removed” - those are actually illegal (in America).
I have not used Ubuntu enough to say I have a bad experience with it. I know of Snap being effectively a proprietary store (a dumb feature) and Canonicals has a bad reputation for being like the Microsoft of GNU+Linux.
Linux Mint offers the pros of Ubuntu but with the cons of like-Microsoft decision removed, why would I consider Ubuntu?