Should I seek a second opinion?

My baby girl is now 9 weeks and 2 days. And even though her dr isn’t worried about her weight, I am. She was born 7.4 lbs and is now 10.3 lbs as of April 4th. I exclusively breastfeed. I do not have a supply problem, as I can still pump about 3 oz after feeding her. My concern is her lip tie. Most of the time she can’t latch on right. And I’m talking about 90% time. I’ve noticed she’ll only feed for a short period but more often throughout the day, about 10 mins on one side and then eat again about 1 1/2 hours later. She’s perfectly fine during nighttime. Thankfully she doesn’t have a tongue tie as well. Turns out, me and her dad have both. Which makes more sense because I have a ton of problems that come with tongue ties, including speech problems. I told her Dr about March 27th and she said that lip ties don’t interfere with breastfeeding. And when I reminded her on my baby’s 2 month check up, she had completely forgot about it and said the same thing even though my baby girl’s latch is getting worse. I have tried every technique in the book. Even the football hold doesn’t help. There’s literally studies done on this, and her pediatrician refuses to do anything about this. Please, mommas, I need advice and FAST!