I read somewhere that he won't debate on ABC due to being involved in a lawsuit against the network and its lead political commentator. But, he has agreed to debate her on another network although I don't think she has agreed to do so. I would think that would take care of the "He's afraid to debate her" talk but there's probably too much propaganda value in maintaining the illusion of fear.
At this point, I'm thinking there won't be any debates at all among presidential contenders since Trump's team wants him to stick to issues rather than personal attacks and Harris' new team want's to limit her to scripted public speaking whenever possible. We may have to settle for the #2 spots verbally slugging each other for our entertainment.