RailFans don't miss their train. Why? Because they go to the station HOURS before the actual departure of their Train - to watch OTHER trains depart. - Prince Maan

Rewa Satna is 40 minutes max, Rewanchal Express does it many times and stops at Kaima for clearance.
Prayagraj to Delhi would be 6 Hours.
Only thing is Satna Prayagraj has to be done in 1 hour 45 minutes which is if course impossible given current state of tracks and 130 MPS clearance upto Manikpur only (trials were done some years ago and Prayagraj Duronto was considered to get the same).
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morning departure and midnight arrival won't matter as AC coaches would get filled mostly from Satna and Prayagraj only, jisko Rewa se genuinely jaana hai uske liye timing se zyada fark nahi padega.
Running morning Vande Bharat Express from Satna would be a maintenance issue, but yeah rake could be bought to Rewa on some days of weekend for same.
But yes for the sake of Prayagraj, Morning Varanasi Vande Bharat Express would be a far better deal.