Question, you say your supply is plenty. Does that mean abundant or just enough? I ask because if you have a large supply or OALD your baby may be compensating with a poor latch. Meaning, he is clamping to slow the flow down.
I also think that it just takes a bit of time. Assuming latch seems fine, you have adequate diaper output, he may just need to grow. It took my son 3 weeks to even latch after having his tongue clipped. I think he just needed time to grow and make it work. Have you seen an IBCLC?
If you obey all the rules, you miss all the fun. - Katharine Hepburn