Zelle users can be both business and personal accounts. Both are fine to use for trading on Bisq.
Currently Zelle business accounts are not able to receive payments from Zelle users that have only enrolled in the Zelle app using a debit card.
Recently there was a case when a BTC Buyer took an offer from a BTC Seller and was unable to make payment as they had only linked their debit card with Zelle, not their bank account. It was decided in a support call that going forwards if this happens again trades will be able to be cancelled with no penalty to either trader.
This will also be the case if a Zelle business user buys BTC from a BTC Seller that is a Zelle user that only has their debit card registered and cannot accept payment from the BTC Buyer.
In both cases above the user that has their debit card registered can choose to link the bank account and complete the trade, or, ifi they prefer not to, cancel the trade with no penalty to either party.