Hi Xavier! It sounds like you're working with DataFrames. Are you returning any large DataFrames from tasks?
Prior to Prefect 2.6.0, task and flow results were always pickled and persisted to the local filesystem. This can add significant overhead if you are passing large objects between tasks.
Starting with Prefect 2.6.0, result persistence is fully configurable. It is turned off by default, but you can enable it where and when you need it.
So if your code involves passing your DataFrames (or other large datasets) between tasks, it's worth trying a newer release of Prefect.