In the windows start menu search Nvidia control panel open it
Click manage 3d settings tab. In that window click program settings.
then click add and find the freelancer crossfire exe (it should be near the top if you recently opened crossfire it will show up as freelancer.exe ) click it and hit add selected program.
scroll down the specify the setting of this program list until you find the setting OpenGL rendering GPU click it and in the drop down menu select your RTX 3080 and hit apply.
I would do the same for the LauncherUpdater.exe just to be on the safe side.
If for some reason the exe's are not in the list you will have to hit browse and navigate to them manually. Both are in the \Freelancer Crossfire\EXE folder