Here is a small application that reproduces my problem:

import fastapi
import logging
import loguru

instance = fastapi.FastAPI()

@instance.on_event("startup")
async def startup_event():
    logger = logging.getLogger("mylogger")
    logger.info("I expect this to log")
    loguru.logger.info("but only this logs")

When I launch this application with uvicorn app.main:instance --log-level=debug I see this in my terminal:

INFO:     Waiting for application startup.
2024-05-02 13:14:45.118 | INFO     | app.main:startup_event:28 - but only this logs
INFO:     Application startup complete.

Why does only the loguru logline work, and how can I make standard python logging work as expected?