Move mouse proportionally between different resolution (and DPI) displays

Solution 1:

Perhaps LittleBigMouse could help you out? It's an alpha application, but it seems to be focusing on the issue you're having.

DPI Aware mouse move across screens

Allows accurate mouse screen crossover location within multi dpi monitors environment. It is typically useful when using a 4k monitor and a full HD side by side.

Github: https://github.com/mgth/LittleBigMouse

Download (Releases): https://github.com/mgth/LittleBigMouse/releases

Solution 2:

https://www.displayfusion.com/ has a feature that will mostly resolve this; it's very simplistic implementation. I have version 9.3 - not sure when it was added. NOTE: DisplayFusion is not free.

DisplayFusion > Settings > Mouse Management > Prevent mouse cursor from snagging on unaligned monitor edges