Another X server start failure

Having a Raden 240 (sometimes 250) and an older AMDGPU. The older card is 
deactivated in BIOS but it is been found by the X -configure problem. X server 
did start one time with -config /root/xorg.conf.new, copied to /etc/X11/
xorg.conf, never got back any "blank black grafic" screen. Rebuilt new world 
and the kern with WITNESS option on and option LOCK_PROFILING. Using llvm-
devel is useless in that case, if it doesn't with the 8.0.X. 

Can't enter framebuffer mode, tells /var/log/x11_*.log,  no VESA, no xfcb. 
sddm tells: xauth: bad add command line, bad delete command line, bad add 
commandline. It used to work with even X -configure fatal error and sddm, so 
what to xrite in xauth; normally sddm autoconfigs. 

I guess it's the recognization from both cards, what is the option to really 
and finally deactivate this on-board card on an ASUS PRIME 350 board (I just 
mean NOT to cut the part of the board where grafics situatiated with a laser-
cutter :-) )? This one has never been used as it been too old for good 3D-
Gaming what has been a topic a year ago - not for me, but for a user. 

What's the state of art for 3D-virutal-glasses and gloves? I guess the same as 
with the AI! I guess freeBSD has other functions to do than beeing a desktop 
OS!

Thx for help in advance, 
Yours, Miranda