The Newtonsoft serializer used by PATCH seems to be causing package conflicts with other assets and potentially the built-in Unity version. Rather than fighting through these, it seems easier to either replace it with another serializer altogether, or provide an alternative serializer if you have a problem. Several other JSON serializers exist, it would just be a matter of implementing them within PATCH.
I introduced a new manual JSON serialization that is built-in the PATCH core. It does not depend on any external JSON library and is not based on reflection nor on IL emitting.
Waiting for tests.
The Newtonsoft serializer used by PATCH seems to be causing package conflicts with other assets and potentially the built-in Unity version. Rather than fighting through these, it seems easier to either replace it with another serializer altogether, or provide an alternative serializer if you have a problem. Several other JSON serializers exist, it would just be a matter of implementing them within PATCH.