The recommended QUIC rules set the action to 'deny', but the first rule is for service udp 80/443 any application. Is there a reason this is a 'deny' and not a 'drop'?
HOW TO BLOCK QUIC PROTOCOL
What a difference a Deny makes
There isn't a default "Deny Action" on QUIC, as it is (as you note) a UDP-only protocol. I believe that the default Deny is equivalent to a Drop, unless you check the checkbox on the "Send ICMP Unreachable" option.
"For a UDP session with a drop or reset action, if the ICMP Unreachable check box is selected, the firewall sends an ICMP message to the client."
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