Phoenix ships with Ecto ORM-style-binding to Postgres underneath (usually) for a good reason! :) And if you need that in memory magic where the serial nature of a genserver won't suffice for your load, you basically have built-in Redis with Erlang's ets. And if you really need insane performance on longer-cached items than ets is optimal for, Discord released https://github.com/discord/fastglobal

And if you don't want to put all those pieces together, like you said there's a rich set of modules people have built, like oban. Long rise and live the elixir monoliths ;) (although admittedly even Discord had to swap out some of their most intense functions with Rust, but how many people are writing systems that need to handle millions of concurrents?)