How to get from UX/HCI opinions to knowledge?

Hey IH-Community,

I am currently working on a tools for students at our university to get a better overview of what courses they should be taking next semester. The university's current solution consists of a 7-level-drilll-down menu and gathering information from 2 additional websites to figure out if the classes overlap in hacky ways like Excel - it's a pain.

We are slowly focusing more on UX but disagreements are arising. We both have opinions about UX, but no real knowledge to back them up (both coming from non-design backgrounds). This makes it rather hard to resolve those disagreements. I guess we could build out each option and A/B test them, but with our level of UX knowledge, I think this would be highly inefficient.

My goal is to get a better understanding of the concepts, frameworks, and principles of UI/UX/HCI so our conversations can become more "scientific" and make impactful A/B tests.

What are some of the resources you'd recommend?
I read a lot about "UX Team of One - Buley" and there are the courses and certificates by like UX Design by Google, ...