You seem to be grossly underestimating how difficult what you are suggesting is. If it was that easy, half the world’s special forces and hostages rescue teams wouldn’t be needed.
You are telling me that if China allocated 1 billion RMB fund to 20 of its gazillion drone labs or other enterprises, it wouldn't get something?
sound waves, drones which immediately enter the ship from all entry points and immediately release riot control chemicals or whatever. Sure if you are prepared, you might not succeed but these soldiers are permanently there. And can they be on point with 0 mistakes 24/7? 365 days? year after year? At some point they will slip, they are humans after all
Moscow theatre siege. It’s not super easy or safe to incapacitate with knock out gas. If anyone died as a result you can bet the US and Philippines will spin it like China used chemical weapons, which will be worse than if China just shot them all
This is what you said. Don't change your words afterwards:
With the Sierra Madre, any boarding action is extremely likely to result in significant loss of life, possibly on both sides.
Solutions exists which is why I said the primary issue is diplomatic and not capability
Conventional crowd control methods also don’t work when the target are armed with military weapons
What, and why limit yourself to 'conventional' methods? How are the soldiers breathing? What do they eat, what do they drink, what do they touch. You even forgot about the art of (non-lethal) poison. Or maybe even lethal poison that there is a known cure that can be administrated after the incapacitated soldiers have been captured.
What you wrote is some funny stuff.
If possessing military weapons means that you are invincible, you should disband your intelligence agencies and just go home and play in the kindergarden where "military weapons = invincible"
As I said, diplomacy is the biggest problem not actual capability.