I couldn't find the Korean anime; Geu Yeoreum (the summer) with English subs. Eventually I found the movie version with Chinese and Korean subtitles and I used Google translate to add English subs and I uploaded it on Odysee:
https://odysee.com/@Quagmiretoiletvevo:c/the-summer-movie-koreananime:0
If someone can provide better English subs or find better subtitles please let me know.

Just boosting. I'm still looking for better subtitles.

Found more accurate subtitles: https://odysee.com/@Quagmiretoiletvevo:c/geu-yeoreum-the-summer-new-combined-version:f