FBA but can't win the buy box at all. Is there something wrong with my account?

I went FBM for 2 months but couldn't win the buy box, even on listings where no other sellers are selling, Amazon didn't show my offer at all.

Now I have gone FBA, everything looks good, I am the cheapest, but Amazon would rather show an offer of "Usually dispatches between 3 and 7 months" that costs more than my offer. Simular story on my other listings where Amazon would rather show US offers than my next day prime for less. On all my FBA listings with quantities, it shows a tick next to "Featured Offer".

One example: https://www.amazon.co.uk/dp/B08QZJT7T7?th=1

I've been told that I need a mod to look at my account to see what the issue is. I have 100% feedback on 4 orders over 1 year ago.