ohhhhhhhhhhhh, right… how could i forget about this… 
in Steam Deck’s gaming mode, which is using bare wayland (which is a window system that is a SUCCESSOR to X11!.. well, maybe it’s not so “barebones” as it is literally always in its exclusive fullscreen mode governed by the gamescope compositor - but thats besides the point!!), were you to try launching the NATIVE BeamNG binary from
~/.local/share/Steam/steamapps/common/BeamNG.drive/BinLinux/BeamNG.drive.x64
it then hilariously launches it in 1x1 pixel resolution. but THEN in its DESKTOP mode, aka the normalwindowmodethateverybodyknows, which is KDE (a popular desktop environment) under xwayland, that can run both X11 and wayland apps, beamNG DOES (!) work… except for the horrible screen flickering (epilepsy warning!), not to be confused with screen tearing, which can be fixed with a compositor (unless you are already running on wayland, which IS a compositor) - screen flickering (blinking) is a FEATURE. that is how it works!
■■■■! to clarify, as i mentioned previously (good reading, btw!), one must understand the differences between X11 and wayland. so, a “compositor” in X11, is an EXTERNAL, additional process. it “helps” with screen tearing. if you are running a xorg session, get picom (github) or something. a WAYLAND compositor, is a complete FULL session, like labwc (github). in SOME cases though, for example, with hyprland, you can apply a window rule to a specific application (which x11 compositors CANNOT do by design, they always composite the entire server/monitors) or allow tearing globally. so, when wayland runs an xwayland application which is tearing, you only have 1 option here: turn on vertical synchronisation. if THAT doesnt help - it is really over. the application was most likely compiled exclusively for xorg, and there is nothing you can do, but switch to xorg (x11) session yourself. i recommend leftwm (github). wayland by design renders x11 frames like this - with black screen buffering. and that is the bottom line.
…
anyway. if you are unable or cannot run beamMP/beamNG NATIVELY (via launching the binary), here are some miscellaneous links to running via wine/proton/STL/lutris. i do not recommend this! go fully native OR ■■■■ ALL. its either all or nothing, dont even bother with emulation!
addendum:
alternatively, SCREAM AT THE BEAMNG DEVELOPERS! directly to their emails from the contact list. scream, scream! you MUST scream because x11 MUST. ■■■■■■■. DIE. nobody should ever make games for x11 in this century. EVER. why the ■■■■ would ANYONE be willing to compile anything exclusively for xorg, a ■■■■■■■ game???! mind you, xorg is a piece of shitware which has a full network stack, a SERVER, all of whihc has 0 security, because EVERY SINGLE applcation keylogs your every input.
wayland or ■■■■■■■ NOTHING.