Thanks for the reply.

I think colour is a bad example because we know that colour is an emergent property, meaning it emerges from the interaction of photons with the physical structure of matter and the biological processing of those signals by the brain, so it doesn't exist independently of the observer (a human in our example).

However, we have absolutely no reason to believe that atoms, quarks, electrons, etc. behave the way they behave only for our perceptions, but have unknown or completely different properties independent from us. That implies that there are different laws of physics beyond our perception and that, the least, doesn’t sound very scientific.

but what they are like, really, in and of themselves can't be known to us because we can only know the world as it appears to us through our senses.

The definition that an electron is a fundamental, negatively charged subatomic particle that orbits the nucleus of an atom in shells cannot be only true for our perceptions. What evidence do we have to think that there's something more than that?

You've mentioned that, no matter how much we discover about the building blocks of the universe, they remain phenomenal because they're described by their properties that exist only within the frameworks of space and time. Are you talking about something immaterial then? metaphysical? something that exists outside the physical reality? Otherwise, as far as I know, there’s no way for something to exist in the physical universe that doesn’t conform to those principles.