i have pretty strong core but i still have a noticable excessive curve in my spine wats the deal?
Lots of things. You should watch some videos about how to fix it. It’s tight muscles and/or weakness at the same time.
I could share some videos but it’d just be me searching YouTube. You can do the same.
As a rule of thumb, these type of posture issues are because one or multiple muscles around the joint or joint complex are weak, not because any are too strong. Weak abs or hamstrings, tight psoas / hip flexors are all possibilities. Luckily there is a huge amount of information and tons of good videos om YouTube that will help you identify and correct it. APT is common so you’ll have a lot to work with.