Dnscrypt-proxy2 heavy load while large file download and video conference

Dear all,
I am running OpenWRT 23.05.02 on a TP-Link Archer C7 v5.
I observed a heavy load on it while and after download a large file or video conferences. There are two processes with nearly 50 % cpu load. One is dnscrypt-proxy2 and the other is a [kworker/0:0X-xx]. X-xx stands for different values. If the heavy load occurs the DNS of the router does not work anymore.
After stopping dnscrypt-proxy2, waiting some minutes and starting dnscrypt-proxy2 again the cpu load is less and DNS is working again. If I start dnscrypt-proxy2 to early the heavy cpu load with dnscrypt-prox2 and the kworker process come back.

What is going on with dnscrypt-proxy2 during large file download or video conferences?

Any help would be nice.

Regards
Norbert