It’s a shame Sentinel is to be broken up for scrap (although there may be ongoing compliance/corrosion issues I’m unaware of). Remove the classified bits and you have an aircraft with a pod and strongpoint underneath, and a separate power system that would be highly suitable for trials of a variety of payloads.
Sad fact is that, given the cost of GLEX parts, they are probably more valuable in $ as spares than as a flying airframe.