Don't waste your time with dns adblocking.
If you are serious about network side blocking do tls interception (lmao) but that is a lot of maintenance, adds other attack surface and the average openwrt device isn't beefy enough for such things.
Firefox and Ublock Origin against ads.
There is cooler stuff for Openwrt. Mesh nets between friends, to share internal services. Just tinkering with and learning about network stuff. Adding ipv6 to tunnel if isp doesn't support. Having Wifi whose autochannel doesn't suck.
Dual Antennas -> Sword fighting. Only fun with multiple devices and dabbling with mesh mode or throughput maxing. In ax dual channel 40mhz +160mhz bandwidth the throughput is faster than some cables.