Currently a high end GPU is required to avoid long render times.

Topaz Labs Video Enhance AI is the best in class commercial AI option. https://www.topazlabs.com/video-enhance-ai

ESRGAN 4 Video is probably the best open source option. https://colab.research.google.com/github/MSFTserver/AI-Colab...

A good list can be found here - https://pharmapsychotic.com/tools.html