On iOS, you can use DNSCloak[1] which has recently been open-sourced[2]. You can either setup a DNS server (DoH or dnscrypt) somewhere that include these filters, or you can use in-app Blacklist functionality to block domain (although it needs domains only-type of block file, instead of host file, but converting them is quiet trivial).
I use PiHole and firewall to manage adblocking at home, and uBlock on every device that supports it. uBlock is a far more effective solution than DNS based ones which is why I prefer to install Firefox+uBlock on Android than use hosts file.
I'll give DNSCloak for iOS a try, thanks for the recommendation.
[1]: https://itunes.apple.com/us/app/dnscloak-secure-dns-client/i...
[2]: https://github.com/s-s/dnscloak