I had the same problem after some Win 10 update or Photoshop update. My photoshop 2020 worked well only with .JPG files but it got blocked everytime I opened a .NEF file (RAW). So I followed the instructions on this link: https://helpx.adobe.com/in/photoshop/kb/acr-gpu-faq.html The section called "Customizing GPU acceleration" worked well for me. Additionally, I deselected the "Use GPU for Display" option.
Then, I accepted everything, restarted Photoshop and... Voila! working. You may try it as well for Lightroom. I hope it works for you.