howdydoody I think most players support SMB and/or DLNA so they are solid options if you want compatibility with different apps and don't want to rely on proprietary solutions. I know HereSphere supports both of them and has no reason to remove either.
Another option is the player-specific APIs. DeoVR has a public API that is very basic that could be enough for your needs. HereSphere has an API too and it's more powerful. I'm not aware of any others.