Found few links about ‘umbrella’ projects:
- Rebar3 Umbrella Projects | Roger's Blog
- Workflow | Rebar3
- Multi-App Projects | Adopting Erlang
- My Erlang project has multiple applications: How should I start them? - Stack Overflow
- How are you building Erlang applications in 2022?
But still have no clue of how to organize code base with Intellij IDE Erlang plugin that will resolve file conflicts.