At least on my end, changing Bottles’ permission settings using Flatseal or KDE Plasma’s integrated Flatpak settings to make it have access to all users’ files makes it work correctly.
Remember to always use the Flatpak version of Bottles, because the native versions are usually very outdated and broken (the RPM version, for example, is totally broken and in a version from mid to late 2022).
Dude, Lubuntu is not made for gaming. For gaming, you would want either KDE (preferred over GNOME due to, among others, VRR/FreeSync/G-Sync, HDR and tearing support) or GNOME.
Regarding the distro:
Fedora and openSUSE Tumbleweed are great options if you don’t usually play for hours, as they are more aimed at general use.
Nobara and Bazzite (both Fedora-based) are the best of the best, for ease of use, performance, etc., with the biggest difference between both being that Nobara is mutable, while Bazzite is immutable.
If you want an Arch-based gaming distro, there is CachyOS, but I don’t like it very much.
I think you can try your luck with either Nobara or Bazzite, they are very user-friendly. I find Nobara more user-friendly, but Bazzite is an immutable distro, so it is naturally more stable, more secure, etc.
I use Nobara KDE, and the idle RAM consumption is of around 1 GB.