You could try some old version of Ddraw.dll (like something from DX9-era) though i'm not sure which one. Also not sure it will work with such a modern GPU.
Do you have any other MWIV contemporary games you could copy a Draw.dll and paste it to MWIVmercs folder?
Most likely culprit are newer drivers for the GPU since you indicate you updated it recently. Unless you installed a whole new GPU?
Either way, as noted, getting old games work on modern hardware can be impossible even. At least old DOS games can be run with DOSBox... Unfortunately there's no old Windows emulator.
(Technically you can run DOS-based Windows with DOSBox and you could theoretically run something on that emulated Windows but... well, i'll leave potential troubles up to your imagination.)
I'd recommend asking from some suitable tech help subReddit, with such large volume of users finding a solution there might be quicker or easier.