If you're in dotnet land, I'd recommend looking at magic onion [0] or memorypack [1]. It'll be much nicer to work with once you have a decent pile of message types. Otherwise it's easy to end up in an entity framework like situation where you're constantly serializing and deserializing, generating serializer wrappers, doubling up on dtos and schemas, etc. Although any of the cysharp libs are great in dotnet, definitely recommend checking out their back catalogue.
[0] https://github.com/Cysharp/MagicOnion
[1] https://github.com/Cysharp/MemoryPack