Applying for STEM extension

I have an approved EB-2 NIW and I am considering applying for STEM extension before filing my I-485. Am I able to do so? Will the USCIS be suspicious of my approved NIW and deny my STEM application? Or should I try to persuade my employer to sponsor H1B?

to Evan:

I think you need to check with your F-1 university about this. I heard from a friend that OPT STEM might be rejected after filing I-140 so I checked with my university about this. Luckily, the university was willing to extend my I-20. So I still got OPT STEM after filing my I-140.

If you are able to get H1B, it's probably a better visa to have but you will probably need to go through the H1B lottery. Good luck![

to Evan:

Yeah go check with your university. I think most school don't mind extending your visa even if you have an approved NIW.