Not a person you are looking for comments from but here in MN we walked away from an ICF home because it's impossible to 'update' expand, make changes to.

Thx. Appreciate that. We figure if we go with concrete we’ll need to be extra thoughtful ahead of time

ICFs have limited potential for drying to both the interior and exterior of a home. I don't like them for that reason.

That said, the interior environment in a home should be regulated by the HVAC system-- not by random air infiltration. In your climate zone, design of the HVAC system will be critical for maintaining relative humidity below levels that support mold/mildew growth. Make sure you've got a professional designer on board and that the design takes into account the low air infiltration rate. In addition to a system which dehumidifies well, you'll need a fresh air make up system such as an ERV to bring fresh air into your home and exhaust stale air.

Had a good conversation with a transparent builder in PC.....explaining the goodness of concrete block with poured concrete and rebar in the spaces.......on a new vector with that