Hi. is there any solution that i could use to have DNS security in my LAN similar to DNS security I would like the router to be able and block different kinds of harmful sites, also manually block sites eg block *.example.com
you can assign the adguard DNSes to the clients you want to filter https://adguard.com/en/blog/adguard-dns-new-addresses.html
https://openwrt.org/docs/guide-user/base-system/dhcp_configuration
if you want a DIY solution, install banip or adblock packages.