I have used Django a lot for applications where front-end is server generated HTML page with templates. For REST API or GraphQL minimalist framework like CherryPy, flask, bottle and others combined with excellent Python libraries will work great even for a large modular app.
It is not true when you recommend don't use flask or bottle for large apps. On the contrary it will be good for large projects to use minimalist framework as they will act more like library. Also you can write code yourself for the parts in the system which outgrow the framework. My team has built large production level application for machine learning service initially in Django and then later ported completely to flask. Given we don't use templates and jinja2 as most of the front-end is in SPA, flask has been wonderful to work with. Django rest framework doesn't work that well when you just need to work directly with request/responses. Blueprints made it so easy to write large modular code that choice between monolith and micro-service, just a configuration setting coupled with either gunicorn or uwsgi in emperor mode.
All Python framework under the hood are WSGI or ASGI, so a decent Python programmer can use excellent marshmallow, sqlalchemy, alembic, celery and flask (or others) with blueprints to write a performant large modular application and a service layer.