I think I'm going to find this one extremely frustrating. I'm going to eagerly read each chapter hoping this is the one where this pseudo-couple turns serious. Then being totally totally bummed when it's not.
I wish they put series like these under another tag other than yuri, so yuri purest like me don't end up banging our heads against the wall, in frustration, every time a new chapter gets posted.
I thought the subtext tag was supposed to be used for that and changed to yuri when it becomes appropriate. I figured the uploader knew something we don't (either because there are more untranslated chapters, author commentary or magazine it is published in) and that is why it got yuri right away. But if not I think subtext is more appropriate for now. Then again, I think all the author's works are yuri right? So it is probably fine. Probably just a slow burn.
I agree that looking at the work so far on its own, Subtext would be more fitting. There's definitely something going on so I wouldn't say it's not a yuri work, but it's a more subtle and indirect approach than what I'd call explicit.
As for official designation that I could find, on X/Twitter the creator promoted a preview of chapter 1 with the "original yuri" hashtag, and on Pixiv Comics the series is under the yuri category.
Given the official designation and the creator's other works, I think it's fine to keep the tag, but whether this series will go beyond subtext seems quite uncertain to me.