No it is, as far as I could come up with.
There doesn’t seem a way to trigger a flow with a variable holding a timestamp.
This is AFAIK only possible with the already mentioned “Every x minutes” trigger.
I don’t see a disadvantage, as long as you don’t trigger a flow each and every second so to speak.
For your use case, the proposed once in 5 minutes will most probably do. Add a condition “it’s nighttime” (which is the “It’s daytime” card inverted) to stop the flow from checking the timestamp during daytime.
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I have been trying though… but I can’t do without the every x minutes trigger.
So the flow concept below is just pretty useless to me.
But, maybe the flowcards used brings you to ideas (or questions) 
