advice?

My docs are the same way. What I've learned about supplements I've learned from here. It's all about trial and error. So whatever suggestions you get here you need to remember what works for one may not work for another. The most important supplements I can think of at the moment is to take probiotics and a multivitamin. It took a couple tries for me to find the right probiotic and I take a vitamin designed for IBD'ers called Forvia. I also take Biotin because I was getting deep horizontal ridges in my nails due to D. Biotin is mostly created in your large intestine so if one is having D multiple times a day it can deplete this.

I also picked up on supplements and alternative approaches from my own initiative and research - it did not come from either my GI or my primary care physician.

However, I think you are wise to check with your doctor about the various supplements you are considering. I told my GI exactly what supplements I wanted to try. As it turned out, she was familiar with them and gave me the green light - which gave me more confidence.