If you want to build a business: Just use Django (or Rails). Avoid all the other more complicated things.
If you care about performance and being productive: Go
If you want to play with new tech: Rust
If you care about performance and being productive: Go
If you want to play with new tech: Rust
FastAPI is on the rise for python and is also something to consider if scaling is a concern.
You can build your entire startup with JUST Django or JUST Rails. That’s frontend and backend. Flask/CherryPy/Express just give you the backend and leave you writing JavaScript for your frontend.