While I'd like to get into doing some bikepacking, multi-day events don't really appeal to me in the same way as a long single day race. Preferably not one that does multiple laps of the same trails though.
I've looked at this event before, so might just keep an eye out for if it's still running next year. 65km of The Peak District sounds about the right level of challenge I'm after :-)
Came across this today: https://moorsonehundred.com/
It might not be tough enough for you but looks like a good event.