The problem is that I have 27 devices which need this control on the dashboard. Isn't there any other way but to copy and paste 27 times this flow on the same page? I will go crazy in that case...
There is some work being looked at to enable ui nodes to exist in subflows properly. You would then be able to put your flows into a subflow and then an instance of the subflow for each device.
However I don't know when that work will be made available.
So yes, in the meantime, you'll have to copy and paste a lot of flows.