Solution found!
I had the same issue with the Ultra-lightweight gaming mouse that came with the MSI Aegis Gaming PC (AMD Ryzen R9-7900X/32GB RAM/2TB SSD/RTX 5080/Windows11).
The mouse was seemingly functional on most parts, but the cursor didn't move (if you could find it). I raised a ticket with MSI as my computer was still under warranty and they sent me a new one, which i received today.....same issue.
Upon further troubleshooting, I discovered that it won't work on traditional mouse pads or any black surface. Once I remove the mouse pad, the cursor began to work - directly on the surface of my table (wood laminate). I tried it out on a black workbook - no movement, tried it out on a piece of white and then green paper - no issues. Not sure why MSI didn't share the solution or recommend any troubleshooting, would save them some money.
In any case, I ended up purchasing a Logitech G502 wireless because it's simply a better mouse for gaming and I gave the MSI mouses to family members.