Precision 7750 lagging UI performance after BIOS update

I updated the BIOS and drivers for my precision 7750 on 8/24/2024 and immediately felt the UI performance became horriably lagging. The most noticeable issue is that minimizing or maximazing a program will freeze a few seconds. 

Here's what I tried so far:

• Rolled back the drivers but failed to roll back the BIOS getting a warning "BIOS Update blocked due to unsupported downgrade". > not fixed.
• Updated all drivers and BIOS to lastest versions > not fixed.
• In Nvidida control panel, set Nvidia GPU as default. > not fixed.
• Did hardware scan and system scan. Everything looked good > not fixed.
• Uninstalled device and drivers of both intel and Nvidia GPU, then installed drivers again. > not fixed.

I am still covered by 5-year Dell ProSupport warranty. Despite informing the technical support the issue started immediately after the update of BIOS and drivers, I need to rollback but failed. The technical support still asked me to update the BIOS and drivers to lastest versions, and then requested me to run hardware scan and system scan, which obviously didn't help and I emailed them on 9/4/2024.  After 4 days I got a reply if I still need support. I am pretty disappointed.

Any idea or any one runs into this issue? My precision 7750 ran strong for 4 years but sadly, not any more after the update.