Some additional notes after doing some more digging. It seems they've drawn additional things on Pixiv that we don't see here on MangaGo like Takeo's training period and the Giyuu initial confrontation. It also seems like the artist has finished the AU(?) as I found some panels of the final Muzan Sunrise Countdown Arc unless it was just doodles.
Someone also posted more chapter scans on Wattpad tho it's in Thai
https://www.wattpad.com/story/275244063-kimetsu-no-yaiba-%E3%80%90-takeo-x-tanjirou-%E3%80%91-%E3%80%8E-fanart-%E3%80%8F
【[竹炭]竈門竹雄X竈門炭治郎- 告白】 https://www.bilibili.com/video/BV1ZU4y1Q7r6/?share_source=copy_web
Additionally, a bilibili video to go along that they made
holy moly the timing, the artist posted new artwork of their childhood together today. last post being november last year
https://www.pixiv.net/en/artworks/148898459
I tried to look for raws but I did find the artists' pixiv and x if anyone wanted to see more artwork and doodles of this AU. I believe the only way we can read more is if someone buys the volumes..
https://x.com/Youshima5
https://www.pixiv.net/en/users/3727139