I also wanted a skylight but wanted to keep the hatch functionality at the same time, so I basically cut a square hole in the hatch and then screwed a piece of Lexan over it: https://www.skoolie.net/forums/f11/r...tml#post446769
. It later broke slightly but it will be an easy fix.
Your current hatch is broken but it might be easy to source a replacement for it that you could do this with. The bus I drive for the school has your style of hatch and I really like the way they can be locked in a position a few inches up off the opening for ventilation. My hatch had a built-in separate vent but that came out when I cut the square opening in it.
You could also install one of the semi-transparent MaxxAir fans in your hatch in a similar way, giving you light and ventilation but still leaving you with roof access.