300 people can do more then 1 act in 1 month. You can make all of act 1, 2 in 1 month if work flow is done correctly. I made a 50 map pathfinder campaign [urgir, Mandev, custom city 4x size of bg3, level 16, the entirety of the land of mammoths, in less then 2 weeks myself using solasta game engine DM maker. People think it's hard... it's not. Only reason there is so much missing content is because the devs where lazy to complete it.
You do realize that Pathfinder maps require ZERO mocap and voice over?
The cutscenes and acting in this game is minimal. They use procedural cutscenes which means all they got to do is record emoting once and never again. They reuse it for many dialogue. Voice acting is not hard. Yes you can only do it in 4 hour segments due to exhaustion etc, but it's not hard. Designing maps is way way harder.
