Underground construction is really hard to do correctly. Partial earth bermed foundations as you mentioned are a good compromise, especially if the earth is built up. But even then, drainage and soil pressure are big engineering concerns.

Also you have no control over how much thermal interface you have. My office is on the first floor on a slab. It's great in the summer and freezing in the winter, despite a carpet.

Digging down becomes increasingly expensive vs equivalent volume building up.

Why not just use ground source heat pumps? It's much easier to bury some tubes than habitable spaces. It's easier to move heat/cold where you need it. You aren't forced into a fixed thermal flux.