it seems that by not setting an environment the default environment is used. The default environment loads the default executor which is the localExecutor which the docs say

An executor that runs all functions synchronously and immediately in the main thread. To be used mainly for debugging purposes.

The executor is for a flow run. Not across flow runs. So each of those Flows has an executor

I'm running the flows (each of the 3 is the same flow file registered ) via graphql / the Ui (Run button)

The concurrency limit is not on the agent level. It’s on a Flow level. If you are using Server, you need to write additional code because Server doesn’t have the concurrency limiting.

ok thank you this is already 90% of what I want I guess - where is this code going, inside prefect-core ? I guess instead of canceling I'm able to re-schedule, the runs take arount 15 min so I could re-schedule and then check again for how I understand this

That code snippet would go in the Flow definition. It utilizes flow state handler

perfect - thank you for taking the time to point me to this

Ah well. You need to do both cancel the current and re-schedule the next in the same state handler.

btw state paused has this

`start_time (datetime)`: time at which the task is scheduled to resume; defaults to 10 years from now if not provided.

I saw your response on the Github issue. Good catch and thanks for mentioning!