I use Ubuntu because it’s the most popular and well-supported.
I’m going to be switching to Mint at some point because it’s basically a community-run fork of Ubuntu and I don’t trust Canonical anymore, but it’s hard to justify installing my OS from scratch considering I’ve been using Ubuntu since 2017.
I recently ordered a Thinkpad T14 Gen1 with an R7 4750U, 16GB of RAM, and a 512GB SSD and you better believe I’m going to be putting Mint on that as soon as I get it.
I use Xfce, as do most of my Linux friends, it’s lightweight and simple yet also very customizable.