If I didn't have a team to deal with a large Elixir codebase (a common issue), I'd glue PHP and BEAM together anyway, even going as far as to pass along the "meat and potatoes" backend work to PHP even for socket interactions (or in some asynchronous way, as needed). In that scenario, the Elixir sockets frontend could be fairly minimal, both in terms of codebase and DB interactions, and would possibly not need a lot of code changes over time.