H1B->F2(Receipt)->H1B(can join on H1b receipt?)

My H1B Stamping and I-94 got Expired on 4/24/2020, Hence I had to move to my wife’s dependent as F2 to maintain the legal status(meanwhile my Employer had file my GC and it was in the process , also I am on LOA(leave of absence)after 24th Arpril) my six years on H1b has been completed on 4/24/2020 and just left with 2 months of vacation capture which my employer did not file for an extension.

Now I am on F2 receipt which is not approved yet, my I-140 got approved and I have filed for H1b extension in premium and got the receipt -1797-C .

In this situation Can I join my employer back on receipt or I will have to wait for my complete h1b approval? I am asking this question because my base petition (legal status F2) is not approved yet.

Please help me with your expert opinion.