I wish they would offer support for local DNS or let me run my own DNS server. Having to remember so many IPs is inconvenient and regressive.
The tricky part of ZT-only DNS would probably be making it work for more than one network at once. So you couldn't send all DNS to one place that serves *.myzt.example.com and recursively resolves anything else, because it wouldn't know about myzt-2.example.com.
Edit: a Route 53 map of your network may be easier to achieve if you use the terraform provider, which I have let languish for a while and should probably give to someone else to maintain (ZT people -- want to take it on? You've got Go expertise now!): https://github.com/cormacrelf/terraform-provider-zerotier
mDNS works fine on zerotier for me at least.