That's like 75% of the work for BG3. There's absolutely some work implementing DnD mechanics into code and designing encounters, and obviously the assets for the world have to be created as well, but the vast majority of their time was spent on dialogue choices and designing the story in general.

It's a great game for it, but we're a good ways away from being able to do the same in an FPS/TPS with real time combat that isn't absolutely brutal. BG3 could be what it was in terms of interactions because it was a CRPG. But it had to be a CRPG to do it. ARPG isn't the term for what Starfield is, but games with reasonably rewarding action take too much work on that element to invest the time into every encounter that BG3 does. Balancing probabilities and maps for encounters for a CRPG isn't trivial, but it costs way less to do than building out all those mechanics and skill trees into real time physics.

They're different games with different goals.