I've also looked at the concurrency limits for the work pool and queues and everything reads that this is only set at the flow run level, so this has limited use if you have flows with many tasks I've looked at the tag based concurrency limit for tasks, but that stops more tasks moving into the

Running

state and still creates all the tasks at the same time so as far as I can tell doesn't actually stop us hitting the rate limit because all the creation events happen at the start (it might help us not hit the rate limit multiple times due to changes of state, but the actual creation events are still happening) Are there any other avenues I can try that would reduce simultaneous API hits (and therefore the rate limit)?

Let me gather some more info and follow up with a final response!

Ok so final confirmation that I've checked @Rasmus Berntsen @Joseph Thickpenny Ryan -- Rate limits are hit through the Create Task Run and Create Flow Run calls. You can see these in your logs as well. So, for example, if you have something that maps over a task / for loop / etc. each time it creates a task run it will count towards the rate limit. If you are hitting these and have attempted concurrency and retries, the best option is to then increase your rate limit, which comes with an account upgrade.