That kind of makes me wonder if quantum mechanics is necessary for gravity to work properly. Like, without tunneling, photons wouldn't be able to escape the gravity of the particles that they originated from resulting in a dead theoretical universe.
Like, how far below the Planck Length can things go in practice?
What "New Physics" can describe interactions on those scales?
Is space fundamentally granular or continuous?
Is it possible that the electron is a composite of smaller particles, just as the proton is a bag of quarks?
And related to your own musings, what role does quantum foam play?
It's all extremely mysterious and tantalizingly out of the reach of the best conceivable instruments.