It's not "rendering" with gaussian splats. It's more "training" (or "fitting"). And not knowing how much the usage vs compute ratio is, I would hesitate to comment.
But knowing a little bit about gaussian splatting, I can't think what manual steps requiring human assistance are even likely to be necessary?
Sure, in production envs I have seen humans being used in 3 places:
1. the pose data calibration
2. cleaning up covariances (reducing blobbiness)
3. adding metadata for app usage
But, to your point, hard to say which of these or any apply without more info. I would be very very impressed if there were no humans and it's 'just' a training time issue though!
But knowing a little bit about gaussian splatting, I can't think what manual steps requiring human assistance are even likely to be necessary?