Having debt is not an automatic red flag in and of itself. It’s failing to deal with that debt (or failing to be in the process of paying down that debt) that is a problem.
It’s a good thing to keep an eye on, but the response to the debt is more telling.
I'd rather choose an imperfect partner that has the courage to take personal responsibility and work visibly on making changes for the positive than some person that has a near perfect behavior but can't see at all nor takes responsibility for the ones' he or she does have. Usually people like that are judgmental, blaming, hypocrits and difficult to truly grow together with over a lifetime. We all have different preferences though.
The red flag for me is his statement that he wants her to basically hold him accountable, be his ‘accountability partner.’ Why can’t a man hold himself accountable? Sounds needy and weird to me.