You can use multiple GPUs with the miner as far as I'm aware.
I can't find that feature, might be something to suggest using the Feedback button or the Crypto Forum Section.I saying that you might want 2 GPU's, one to mine and the other to use like gaming.
Please press the "Send Feedback" button in the Miner and explain that your GPU is not working. See this thread on how to submit Feedback to the Miner.HI
I have Nvidia Geforce GTX 1050 Ti 4GB
Your operating system: Windows 10 64-bit
And the crypto-miner is telling me there is not compatible GPU