Oemojisangjuui

Similarities: The same character situation whom were in the plus size department whom always got themselves bullied, but thanks to some supernatural luck both become hot and adorable. Both bullied character were able to get back at their tormentors. Dissimilarities: One was set in Korean in it's educational setting , while the other is set in Japan in a Japanese educational / isekai setting.  

both are korean media and involves body switching bagel girl has mystery element to it (ugly man into pretty girl) lookism is more about school life (ugly man into handsome man) 

Gets 2nd chance in life and tries his hardest to change. But its isekai. One of the best isekai in my opinion. 

The main protagonist is Bullied and harassed for his body and ugly looks at the beginning but soon he overcomes that fact and becomes very popular. He sets his life to revenge or to make the things right by using his popularity and good looks. Masamune kun is a japanese anime on the other hand lookism is korean adapted from manhwa. In Masamune kun the story focuses on romance and slice of life whereas lookism focuses on fighting and drama more. But the two of them has similar story setting. 

Both main characters are very popular because of their looks and everyone gets excited when people see them(handsome/beautiful) Both of them comedy/drama komi-san is much more comedy and other one is more heavy theme/bullying etc -school setting -heart melting scenes 

Both about nerds that had a body change and become popular on school, good comedy with good characters  

Both anime are about people that have a power that permits their souls to go in different bodies. 

Both recent anime adaptations of massively popular Korean Webtoons. They both have famous K POP groups involved in their respective OSTs (Stray Kids & ATEEZ). This gives both shows a similar vibe across the board but especially in their music/OPs/EDs. They both also have unique and distinct art styles that make them stand out with their own signature looks.  

Blockbuster webtoon household names finally break out with their own adaptations. Both kicked off to a relatively lukewarm response from their hardcore fanbases yet both likely at least performed well enough to be branded successes. Both also have a school setting and a positive/wholesome vibe to them. 

Both have supernatural school settings and are adaptations of massively popular Korean Webtoons. The reception of both from their fanbases left a lot to be desired. There are also similarities in their OSTs that leads to a similar vibe from both shows. 

same bullying/appearance issues with both MCs who were originally fat/ugly except Beauty Water is more on the horror/thriller aspect 

Both main characters get a second chance at living how they want to. They both go through struggles, but they end up able to make friends and also discover another person who has the same supernatural life-changing experience as they do.