My parent's home, where I grew up on the South Shore of Boston was $12K in early 1950s. Sold for $300K in mid-00s. Later torn down for a McMansion.

None of the things they did actually increased the value; updated kitchen and bath, single car garage, detached shed, etc. It was always proximity to Boston and T.

Per your question, I would be wondering if you're buying into a bubble and any delay would be to your advantage. Similarly, although there does appear to be minor slowdown in interest rate hikes, but these are truly unpredictable until a lot of what spooks the market gets settled.

Would it be possible to add a garage or carport without needing a rebuild? That may buy you a year or two to revisit the question.

As for schools, no idea what 'A niche' means, but lobbying for new taxes for schools usually goes over pretty well in Massachusetts. Also, money saved by deferring the rebuild could be put towards an A+ private school.

High rates can be bought down if you opt for either of your proposed options. My 14% mortgage in 1980 later became 5% seven years later.