I feel it's best to not really say anything of substance. You're not there to proffer advice, and it's not like they are disposed to listen to (what will be per

I feel it's best to not really say anything of substance. You're not there to proffer advice, and it's not like they are disposed to listen to (what will be perceived as) the disgruntled ramblings of someone who got fed up and quit. To them, when you quit over problems in the organization, it doesn't mean they need to change, it means you "couldn't handle it". Basically, offer them your consulting services if they are actually interested in fixing their problems (spoiler: they're not). Everything else, keep it super anodyne and say the functional equivalent of nothing.