H-1B Transfer from company W to Company X on receipt of the transfer

[fj_123]

Hello Everyone ,
I currently work for employer "W" on a H-1B and have received an better opportunity from other company say "X" .Since the USCIS has currently suspended premium processing for all H1B's premium processing is not possible . So the new company "X" is asking to join on the receipt of the H1B transfer .
My question is what is the risk of joining company X just on the receipt of the transfer and what if I join the new company after which I get a denial for the H1B transfer ? what will be my status then and what can I do about it ?

Any help would be appreciated .

Thanks a Lot !!