If it is available please consider looking for the tankoubon release as it is said to have extras and different angles for some panels. Thank you for your work.
@Ranumata on pixiv this is listed as ch 43. Do you plan to go back and fix numbering to account for the R18 chapters? There are several missing on mangadex that are on pixiv, and so the numbering here seems random.
To others: there are many more R18 chapters on pixiv sprinkled throughout, as a...
I think the bonus page is from the artist's "other" account on Twitter, which can be reached through their "other" pixiv. They have some extreme versions of some pages of this manga as well.