Clearly, neither dere type participates in healthy, ethical forms of romance, but since they both tend to be so violent in their methods, it's easy to mistake one for the other despite their otherwise obvious differences.

Source: https://www.cbr.com/anime-characters-yandere-vs-sadodere-main-difference/

It's understandable why this -dere type is criticized, but these characters often have unmatched emotional depth and tend to be extremely well-written.

Source: https://www.cbr.com/tsundere-love-interests-popularity-in-romance-anime-manga-explained/

Like any other "dere" type, tsunderes are mostly female.

Source: https://www.cbr.com/fan-favorite-tsundere-anime-husbandos/

The number of -dere types in anime is never-ending, especially considering the vast personality types present in anime.

Source: https://gamerant.com/anime-best-oujidere-characters/

They always seem extreme, but this dere type boasts red flags of many shades.

Source: https://www.cbr.com/anime-characters-yandere-vs-sadodere-main-difference/