Advice on buying new Primary & sell current Primary + Rental with existing mortgages

[Sumedh Jigjinni]

Despite these crazy times of high interest rates & strong property values, I am considering purchase of a new primary residence. Primary residence is valued at 2.4M, 1M left on loan, and at 2.375% IR. Rental property is valued at 1.2M, $480K left on loan, and at 3.50% IR. Currently renting at $4k/month. Ideally I can keep existing mortgages because of their great rates by porting, take advantage of appreciation, avoid as much taxes since sale will be for new primary residence, and still come out on top with a more expensive primary residence.

Would love to understand what is realistic, what other info I need to provide, and any other strategies given the market.

Thanks!