I've had no problem with Zelle other than if you have multiple accounts, you need to set the correct account as default before receiving the transfer (as the seller.)
Zelle is integrated with many big financiall institutions. The risk is all on the buyer if the seller is a scammer.
It works just like a wire transfer, (but there is no fee, and you can do the transfer by logging into your bank's website.)
I've used it with pinsiders sending them money, trusting their reputation / length of pinside membership.
If you are the seller (recipient) and both parties are Zelle members, your cash is safe and cannot be backed out once it is received.
Zelle is perfectly legit, but you gotta trust the seller.
It's super easy to sign up in Zelle. And will automatically work if both party's already bank with member institutions.