Please, for the love of all that is holy, stop blocking ICMP! It's needed for things like Path MTU Discovery. With the increasing use of VPNs and tunnels (IPSec, Wireguard, GRE, etc) PMTUD is more important than ever.

At a minimum, any node on the internet routing or serving traffic needs to keep ICMP open. If you're running a DNS server, ICMP should be working.