Fedora or OpenSUSE. Either “just works” with very little setup or fuss. I still recommend Fedora to most new users who want a general purpose OS, but OpenSUSE is very similar with the added advantage of not being sponsored by a giant, openly evil corporation.
If you want your device to be primarily a gaming device and absolutely are not a Linux tinkerer, Bazzite is a great pick. If you do like to make the OS “yours” then skip Bazzite.
I recommend avoiding Arch-based distros like Endeavor or Cachy, though they are very popular. Nothing against them, exactly, I actually really love Cachy, but the AUR is dangerous and cannot be trusted, and I don’t want to have to obsessively vet packages constantly.
Definitely don’t touch anything Ubuntu. If you want Ubuntu compatibility, give Mint a try or Debian 13 with KDE.
If you want to test drive a bunch of distros, find a spare thumb drive and install Ventoy. Ventoy lets you easily put as many ISOs as your drive can hold into a folder and just as easily select which you want to boot with. It’s a great way to try things out quickly and easily before you settle.