I’ve been a Pop stan since I started using Linux so I’ll always recommend it, and it helps that you already like it. But if you specifically want something different (and that isn’t arch), I’d say Fedora KDE

That’s carrier unlocked. It means you can connect your phone to any carrier you want, as opposed to when you buy the phone from the carrier, who typically keep the phones locked to themselves (for a certain amount of time)

Do any of them come factory unlocked? As far as I’m aware all Samsung phones made in the US are locked down

Where do you live? Samsung phones in the US can’t unlock the bootloader