I have owned my FLATED camper top for about 7 months. So far I have camped enough nights in it where the rain got inside because it was either have the windows open for some ventilation or bake in the heat.
I finally got around to solving the problem for myself.
I made some vents that fit between the velcro of the window panel and the camper top so you can just use the velcro to keep them in place.
https://makerworld.com/en/models/2946271-flated-camper-shell-window-vent#profileId-3300361

