Related thread: https://news.ycombinator.com/item?id=34530052
Recently went through this discussion with two friends. For now we are doing PocketBase for a simple, extendable BaaS, Flutter for front-ends.
We are starting to drool looking at Elixir, Phoenix, and LiveView from afar. But the learning curve would slow us down for the next MVP that we need to put out on a schedule.