Star Vs The Forces Of Evil and Voltron Legendary Defender are both shows that were critically acclaimed at the start, but by the end, they became heavily divisive. They both have different reasons for seasonal rot. For Star, most people would usually say it's because of interesting stories with wasted potential, the characters becoming more unlikable, the romance taking up way too much screentime, and the unfortunate implications of the series finale Cleaved. For Voltron, the most common reasons not only include interesting stories with wasted potential and poorly done romance, but also with LGBTQ content being tacked on, Lotor's death being seen as too cruel for him even with all the heinous actions he did, and the implications of the main characters not being real friends/family but just coworkers. There are other reasons for both shows, but those are the most common reasons. Both shows also ended at around the same time as each other. However, which show do you think went through worse seasonal rot? There are some people who will defend certain aspects of the later seasons, but it's still noteworthy.