F1 Stamping - H4 to F1 COS Situation - Chances?

I joined Masters program with H4 visa and later converted from H4 to F1 by COS.I completed my studies and currently employed in OPT, Is it advised to go for F1 stamping in OPT / STEM Extension / H1 status?

It is not really recommended to go for stamping for F1. The reason is, it will be very hard to prove the non-immigrant intent as you are moving from dual intent visa to a non-immigrant visa. Read Difference between Nonimmigrant vs Dual intent visa
Also, going for stamping during OPT is also risky as you have already completed studies and working on OPT, they may question your intent to come back as you are working and your education is over…so, it is a tricky situation and you need to be careful. You can discuss with an attorney as well and seek guidance.