The "UHD 620" graphics chip is simply an HD 620 'renamed' ... it has no changes from the 620 internally. They were first launched on gear in August of 2016 as a low/mid-level on-board graphics unit. So it's a four year old bit of low/mid-level on-board graphics hardware. Nowhere near a dedicated GPU in performance.
And that is the problem here ... Premiere 2020 is coded to use a more robust graphics performance than that chip can provide. I don't think the problem is so much "just a driver issue" ...because I don't think there's a driver that could bring that chip up to current needs.