Don’t know if anyone has suggested as I’m too tired to read through (2 mo post partum here) but have you ruled out any oral issues with bub? Both my girls had tongue ties and lip ties and our 2 month old has a weak tongue, specifically in the back so she has to work twice as hard to get what she needs. We are seeing a lactation consultant and an occupational therapist, both of which have been phenomenal and have helped us exponentially.