here's a good earlier thread about rate limiting. It has information on why rate limiting is important to note and how to change it.
In this thread, in 2021, @yubiuser wrote this-
In certain configurations it might be reasonable that your router has such a high number of queries, esp. if all your client traffic goes to your router first and then to Pi-hole. But you should have a look at your queries first to rule out a DNS loop or a client going wild. Do you always see the same queries in the query log?
You can increase the limit via /etc/pihole/pihole-FTL.conf. See the link mibere posted above.