I think we need to replace the word science with empiricism, or else acknowledge that there is both a formal process called science involving laboratories and observatories, and papers and journals.
But science is just collecting data, generalizing by induction, generate ideas that allow one to predict future outcomes, which is validated by doing that. So, what an astronomer does to predict an eclipse is not fundamentally different from you and I do when crossing the street. We look left and right to see if traffic is coming (collect data), conclude that it is safe to cross, and successfully predict the outcome: crossing was safe as the data suggested.
Even with subjective truths, the process is the same. Every time I eat Brussels sprout, I have a bad taste in my mouth. That subjective truth is as reliable and reproducible as any other for me, and also allows me to successfully predict outcomes: If you eat that, you won't like it.
These are truths, too, just not for everybody. But since they are determined empirically, they're science, albeit informal science as I define it.
Finding a piece of art beautiful is also a truth for the individual if that what happens
Solve what? That there are assumptions in science that have been confirmed to be valid empirically (and they have, and that is science, too) by the stellar success of science? The sine qua non of a correct idea is that it works, that it is useful in the sense that it can predict outcomes, like eclipses (for everybody) and the dysphoria of eating Brussels sprouts (for those that have that reaction to them).
I've told you before that I think you make this all too difficult. Ideas that work are correct. If I tell you that I live five blocks north and three blocks east of the pier, and going five blocks south and three west gets me from my front door to the pier, the idea is correct. Is is absolute truth, is it objective reality, can we really know anything, what are the assumptions underlying this belief? How can we knw that the pier is real, or that we aren't in a matrix? I find all of that less than useless. It causes one to be in a state of epistemic paralysis, epistemic nihilism.
What is the benefit to you of this type of thinking and the questions like you ask here? Do you wind up with deeper insights that allow you to make better decisions that make your life better? Are you avoiding mistakes with these ideas?