What to do if I’m running out of the recaptured unused time of the 6 year H1b?

[Oasis2022]

I am using the recaptured unused time after 6 years of H1b to stay in US while waiting for the approval of PERM. My employer submitted the PERM to the Department of Labor in the early April, 2022, but my recaptured unused time only allows me to extend my stay in US till Dec 30, 2022. Here are my questions:
1. What options do I have if I’m running out of time and still do not get the approval notice?
2. If I have to leave the US before I get the approval notice of PERM, can my employer cancel my PERM petition while I’m away?

Any feedback is appreciated!