But surely this question of yours does not relate to a claim anyone has made in this thread? No one suggested maths and art might be "interchangeable". (In fact, as neither maths nor art is science, it seems an odd question to ask in this context.)
More broadly, I don't know whether you are playing Devil's Advocate in this thread, but the stance you are adopting seems to be a rare, actual example of "scientism". (We had a thread on that a while ago in which I argued it is a much-abused term that rarely applies. But here it seems to.) Several contributors have offered descriptions of what spirituality is, and what function it performs in human experience. It seems to me your attempts to whittle that down to nothing are looking a bit unconvincing.
The key, surely, is to realise that individual experience is where everything about the world begins, for each of us. Your world of (supposedly, but never entirely) objective facts and rational deduction is always at one remove from that individual experience. It is inferred from experience and forms only one, rather limited subset of it. Spirituality and science are orthogonal, surely? Why does one have to decide between the two or consider them rivals?
Well, let us start with a classic. What is God? Well, there are several ways of doing that but for a sub-set of Gods,
God is the objective source of what is correct.
Okay, but for a naturalistic explanation it turns out that it is a subjective claim in a given brain. So the general rule for not just natural science, but also sociology and psychology is that in some cases, the following behavior can be observed:
Someone will subjectively claim, something is objective and as long as the subsequent behavior following as the effect of that claim is in fact possible for the world as such, it is happening both cases.
Now that is the general case. So can we find a similar case for non-God claims, where it works the same?
Yes, because science as an actual methodology is not the same as science in effect claiming for what is correct for the world as such.
This is not a critique of science. It is an explanation of a different kind of behavior that uses the same words, but in effect have a different meaning and effect.
So back to God and the many different versions. The same is the case for in effect only objective reality is real as with evidence as per science.
Now the actual words may vary, but it always in effect that only the objective is real.
And there is a subvariant that is really absurd. Everything that goes on a brain is objective and physical, because only the objective and physical is real and with evidence.
Everything in the mind, thoughts and content are in effect objective and physical.
So if we nitpick objective and subjective for their different definitions we can find the following 2:
Something is objective if independent of individual thought and something is subjective if dependent on individual thought.
Such fun.
So what is it that God is the real and the objective, physical reality/world/universe is the real have in common? They are both connected to the fallacy of concreteness, in that both are consider correct facts independent of brains, but they are not.
In effect it is the same cognitive behavior for similar claims for in sense for different metaphysics/ontology, but they end up as being the same psychology.
There are in these debates and not just this one generally always two versions of science at play. The actual science and all the variants of only the objective is real.
Regards.