DNSCloak lets you load a blacklist and/or select an ad-blocking DNS server: https://itunes.apple.com/us/app/dnscloak-dnscrypt-doh-client...

So it's pretty easy.

Does that let you block urls? Like, the way leechblock does on firefox.

I know ios can do this with content blockers, but they only work in safari and are too easy to circumvent.

huh, well there goes my main argument against iOS.

I use https://1blocker.com/ on the iPhone. It’s not uBlock Origin but good enough.