defrecord equality implies matching types. This has been discussed and decided upon such that people should only bother with defrecords when they want an equality partition. There are, however, use cases for defrecords as small structmaps to save memory and those require map-based equivalence. Clojure has a marker interface for map equivalence: clojure.lang.MapEquivalence, which gets used in = to decide whether something qualifies as a persistent map. This can be reused to change the equiv implementation of a defrecord.
When MapEquivalence is implemented in a defrecord, = becomes non-reflexive
Add clojure.lang.MapEquivalence to implemented interfaces in a defrecord, to treat it as a PersistenMap in equality, disregarding the type tag.
APersistentMap.equiv already does this, defrecord implementation can call APersistentMap/mapEquals