Any merchant who's using BitPay should switch to BTCPay Server the soonest possible. It doesn't make sense to use an intermediary for this purpose when the currency's software already exists for eliminating this kind of third parties.

I have never used BitPay, but I'd read somewhere that they even demanded KYC for a purchase. Unbelievable or just reasonable and probable considering today's sniffing standards?

It isn't enforced, but having it as an option officially on Bitcoin Core rather than as a potential change that requires altering the source code:

• Encourages the miners to switch to it.
• Creates a fine mess on the network, defeating essentially the purpose of non-RBF; especially due to the former.