If Celery seems like overkill for your process, and you're really just looking to execute basic cron functioanlity, then why not just use crontab to invoke your Python script?
I can think of two major ways to operationalize a Python script that needs to run continuously. One is with containerization, which usually means Kubernetes, which already has a perfectly fine resource definition for cronjobs. The other approach is to run the script in a bare metal or VM, which would mean defining a service to ensure that the process can be managed appropriately, restarted if it dies, and the like. In other words, defining a service is about just as much effort as defining a cronjob, and there's no escape from some amount of "ops work" that isn't encapsulated in a Python script.
So why not just use the tried-and-true prior art than worry about building and supporting your own secret third thing that others would need to learn, support, maintain, and keep in mind when debugging a problem?