I'd stay away from Manjaro, personally. They've had a number of organisational and security fuck-ups that in my opinion makes it hard to take them seriously. Once is forgivable, but when they make the same mistake 3+ times it's just completely unforgivable and unprofessional.

Plus there's the whole "we hold Arch packages back two weeks but not AUR packages" - which means there could be dependency issues if you like installing stuff from AUR. In fairness though, they do request that users do not install AUR software on their site, so people do get warned about that.

Endeavour is good. If I was to go back to an Arch distro, it's what I'd use hands-down. Fundamentally just Arch with a better installer and a nice theme.

I'd also consider something Fedora based, like Fedora (duh), or Bazzite (if you want an atomic/immutable OS). Up-to-date, extensively tested. Bazzite even allows you to install it with out-of-the-box Gamescope support (in simple terms, you get some of the performance options and performance overlays that the steam deck has).