I honestly wonder, for a team that is unfamiliar with both psql JSONB and mongodb, which of those two would be easier to learn? And later on, which of those two

I honestly wonder, for a team that is unfamiliar with both psql JSONB and mongodb, which of those two would be easier to learn? And later on, which of those two would make the team more productive? I think this is the most important. To be fair, I use mongoDB for 8 years now compared to less that 1 year of psql JSONB, so I can't really answer objectively.