After setup, I recommend restarting the router for the changes to take effect (and computers). Note that OpenDNS is only DNS and there is a DNS cache, and it is important to clean it first.
Turris Omnia with OpenWrt 21.02 - Tested
Linksys WRT3200ACM with Gargoyle 1.13.x
TL-WR1043ND v2 with Gargoyle 1.10.0
http://gargoyle.romanhk.cz custom builds by gargoyle users