What you are describing sounds like scheduled socials to me, just in the office instead of over zoom. But I would not be surprised if mostly wfh with a few in-person days turns out to be the optimal setup for most offices.
You can't schedule a social for 8h/day though. The trick is the informal interactions, e.g. over lunch, or between tasks, or when you overhear something interesting.
Compare e.g. a language course that you go to once per week or day for an hour vs. in-country immersion. similar thing.
