RE: Aspect Ratio of PIP
The only PIP options I see are for size (Small, Large, Fill) and location (page 47). The PIP size does not mention resolutions. A firmware update is a costly venture to Dell. Firmware updates are only provided for issues that are deemed as failures. What you are looking for is something that was not part of the original design.
Social Media Support
Run the PC pre-Windows diagnostics
Where do I find my Dell PC Service Tag or Express service code?
Out of Warranty Support