this looks like software mode to me, you can tell easily because there is no filtering on textures
IIRC you must drop the 3dfx opengl DLL file in the Q2 directory so the game will pick it up and use it - memory is rusty but pretty sure another member will chime in the correct way to do it 😀

Thank you, I will try and get the dll file in the game folder and try again! 😀

If you look at the console as the game loads you can see ref_gl fails and it uses ref_soft instead.

There shouldn't be any need for any extra DLL, Quake II installs what it needs.

Looks to me like you selected standard opengl instead of 3dfx opengl in setup.