Wine FSR variable not working but instead the FSR switch works in game launchers

im using the flatpak version of heroic and i tried to enable FSR. It seems like it works if i enable it from the switch, but if i add a custom environmental variable ( WINE_FULLSCREEN_FSR=1 ) under the game settings ( Rocket League ), it seems to get ignored and not work. The gamescope and inbuilt fsr switch work fine tho. In Steam which i have installed as system package, the flag works fine after putting it in the launch options. Similar case is with lutris also.

I have linked a video, explaining my issue.

https://streamable.com/b8u8ti

Any help would be greatly appreciated.