I love how you found a niche, valuable problem, built a framework, and are seeing a lot of success. A question (and I'm far from an expert so let me know if the assumptions are wrong):
It seems to me that the federated users have to be coordinated around timing for this to work. Otherwise this could take weeks/lots of slack messages for a single model to train. E.G. one team is having infra issues and doesn't get a job started, the other team is ready but then their lead goes on vacation, etc... In the internal-to-an-organization case this is probably fine (E.G. a hospital where the data has to be separated by patient/cohort), but if there are different teams managing the data then (a) have you seen this problem and (b) do you have tooling to fix it?