Interesting. I'm using nextdns on my router, I had manually blocked ads.roku.com and now have the Stephen Black block list enabled too but I'm still getting ads.
Now that I look through my nextdns logs, I don't see my roku at all so something seems to be up with my config. Thanks for the help!
Something to be aware of, some devices will straight ignore your DNS settings in DHCP if they can't get to their ads. My iPhone 13 did that. I had to block port 53 udp/tcp for everything but the piholes.
I'm sure eventually we're going to see DNS over https doing the same and I'm 100% ready to mitm all devices that pull that bullshit..