Why not describing the use-cases you want to implement which you are struggling with? The one use-case I can decipher from your rant is to talk with external devices. In this case the answer is, talk with the device directly. Then you can be sure that your messages are send to the correct device, not filtered or changed in any way by the host.
For articulation: note expression and key switch handling are features natively available in VST3.
Cheers,
Arne