I use Yandex DNS (with filtering of dangerous and phishing sites).
Not sure for malware, but tracker block lists are good.Are the malware lists any good compared to Quad9 or OpenDNS? They seem to be using community ones.
No, you can have AiProtection and still use your own DNS, but Merlin's ASUS builds don't play well with NextDNS for some reason. With Cloudflare, it works perfectly.Hmm, I think read somewhere that if you want to have AiProtection enabled on the ASUS, you will not be able to change DNS?