For example, DNS can perform differentiated resolution for different source IP address lists, as well as FWD and recursive DNS for different operators(isp)
That would be perfect 
Have you tried using the DNS forwarder?
yes ,i did
It forward domain like *.example.com to somewhere , for all the users who use this routeros-dns-server
But in reality, the demand is generally that if I have multiple exits corresponding to Australia, North America, and Europe, and I want different users on the intranet to access a certain website, such as youtube.com, from different regions, then I definitely hope that the IP address he resolves is local. The most direct way is to forward this user's DNS request fwd to the local DNS server
The easiest way to achieve that is to just let the different regions forward their DNS requests to DNS servers local to that area. The DNS for Youtube already does the optimizations you want.
The only problem with that is GEO blocking. With youtube, I think you can use DNS forwarder youtube.com to youtube.uk but that's for all users. To do what your asking, I have no idea if it's possible per user.