Do Bazzite. It will be unbeatable for just working and ease of use.
Stay away from Manjaro for anything.
SteamOS that Valve offers is not the same as what's on the Steam Deck. It's extremely dated and is what it used to be. A real distro from Valve has yet to be released.
The best way to install WoW is using Lutris, which also comes with Bazzite. You search for and install Battle.net, then you can install WoW normally. Lutris can also add a WoW shortcut once WoW is installed, too.
You can also just copy and paste the WoW folder from your Windows Program Files folder. It keeps all your settings and addons.
For addons use Wowup-curse. It's a open source addon manager that is just straight up better than all others.
Currently, WoW needs Proton-GE to work. Using wine-staging, or the dated wine-ge, and Battle.net will have problems starting. It's something weird with authentication and connecting online. Proton-GE contains a patch specifically for this.
The easiest way to get Proton-GE is using Protonup-Qt if using KDE plasma, or Proton Plus if you're using Gnome. For Protonup-QT, you select Steam, then install Proton-GE for Steam. Lutris will also be able to use it.
Just general advice, I'd use the latest Proton-GE as the default for all Steam games.
In Lutris set the runner for Battle.net to Proton-GE.
Source: I've tried all but Drauger OS, and currently play retail WoW.
Mine finally bloomed this past week! I got a wide shallow hanging pot, so the little ones that fall off can land in soil and start even more growths.