

Murena ? as the murena foundation that develop /e/OS ? If yes, their OS is based on LineageOS microG edition with a great ad/tracker blocker and an app store that is kind of a fusion between the aurora store and fdroid (without the ability to add repositories unfortunately, in the version I used at least).
So you can install whatever apps you want with it(Except maybe android auto, I guess). I had my banking app and it worked well (until it detected I was root).
I used it with my oneplus 7, It had some big trouble these last months as their servers were outdated and they needed to update their whole infrastructure. Now, everything seems to be back to normal.
I can not say for their phones (murena 1 and 2), but their OS is solid to me.
For gaming and having it work out of the box ?
Beginner friendly : Mint, most of gaming distro (cachy might be a bit more advanced )
I do not know much about the current state of snaps, so I won’t recommend Ubuntu and derivatives (kubuntu, Xubuntu…). I guess it is easier to use .deb now, but I can’t call beginner friendly a distro that require terminal or tweaks to change packages you can install on it.