I'm aware that this is the "small" Twitter sample. Unfortunately the artist has already terminated their Twitter account (and Pixiv acct) before I could get to & find the un-horizontally-flipped original resolution. Lacking its source now, and having done image search around for other source, for the moment this cached "small" sample is the only surviving copy of it now; unless someone has it locally saved before.
Pixiv src (which has been down now, just referenced by SauceNAO): https://www.pixiv.net/en/artworks/86689083