H1B Transfer New Employer - Join with Email notice or wait for Physical notice

I have my H1B and I-94 valid till 31st Dec 2022.
My got a new job and the employer filed my H1B transfer in premium and it got approved till Dec 2023. Received this as email confirmation from USCIS. Haven’t received any Physical copy in mail yet.

Question - Can I join new employer with that email confirmation or shall I wait for approval notice via mail. I am hearing some transfers are not getting I-94 extended so bit confused.

Ideally, you should wait for the physical copy. So, I would wait too.
Yes, it is a possibility that I-94 may be missing sometimes…