* jitsuyō: https://www.weblio.jp/content/ハピエン
* wikt: https://en.wiktionary.org/wiki/ハピエン

ハピエン	404

https://ja.hinative.com/dictionaries/厨
こんにちは！
すみません、「ハピエン厨」は英語で何ですか？？ とはどういう意味ですか?
It means happy ending addicts. In other words, they are people who can't bear unless the story ends happily.

https://twitter.com/gamemarkun/status/1718988806643499051
私はハピエン厨です！！！！！
ハピエンだいすきです！！！！！！

Stumbled on while looking at 厨.

"ハピエン厨" has 0 ngrams but a mountain of google results, which suggests a significant softening/popularization of the suffix 厨 in the last decade.  I will double back to that.