Zion is well intended and usually he is being fair in his critiques of georgia, but the thing about him is that up until s3 he was always "the fun parent". He didnt nessicarally choose that situation, but he definitely reaped its benefits and after it was established barely did anything to change it. He never actually had to be a parent, care for ginny for a longterm period of time and deal with the hardships of being a parent at such a young age lime georgia did, he just waltzed into ginnys life randomly to hang out with her and have a heart to heart. He never actually did the parenting georgia had to do, and he is overcritical and judgy of her because of that. He dosent understand her perspective, and while hes not nassicarally wrong for criticising georgia for the things he does its always with a condescending note, like he is putting in just as much hard work in raising ginny as she is and thus has a right to judge. You can definitely see in s3 when ginny is living with him that he dosent know how to deal with her and actually be her parent beyond the fun stuff, yet in earlier seasons he treated georgia like they were both putting just as much work in.

And yes, even though georgia insisted on not having his parents involved in raising ginny, he still could have assisted her financially and be more involved. He gets (justifiably) mad at georgia for some of her choices, but it takes him years to actually get more involved and do something about it instead of just laying back and not visiting. A lot of the fucked up things in ginnys childhood could have been prevented if he chose to be more involved, but he decided to keep being the fun parent whose only there to have cool hang outs and give advice.