Actually, it all depends on how many panties the script drops - it’s not guaranteed that 90 will spawn. In any case, the maximum reward is given if you collect 81.
If you’re talking about Season 1, there shouldn’t be any bugs there. The game has been completed many times by me and other players. You should follow the events marked with the heart icon, increase your relationships with the girls, and explore different locations to progress the story. It’s also important to buy transportation.
In Season 2, there are hints for every stage of each quest — both for the girls’ quests and the main storyline.
