There is DNS-over-TLS. The difference between DoH and DoT is that DoT runs over a distinct port, and can be trivially filtered by network operators. DoH was created specifically to run encrypted DNS over a transport that would require more intensive filtering to block. As an anti-censorship mechanism, it's imperfect, but it comes at little real cost (other than preventing operators from blocking encrypted DNS, which is the point).

DoT is, effectively, DoH with a kill switch.

It'e essentially a moot point at this point; DoH won.