I read that participation in RNC debates is contingent on agreeing to support the official Republican convention candidate.
And last I heard, Trump has not done so. It was suggested that he might instead sit them out.
I think the RNC is wrong to ask this commitment, though they reported did out of concern that Trump would not support the nominee. Surprise, he hasn't cleared this up.
Until Trump does, let DeSantis alone as hasn't said anything one way or the other.