In regards to the pacing remarks, I think the only thing to would be to compare progress To other manga (not even necessarily yuri). In Kase-san for example, by page 146, there's already a kiss and an outright "be my girlfriend" declaration. Not "be my friend", but "be my GIRLfriend".
Comparatively, by page 146 in this (of each chapter was 4 pages) we're looking at chapter 36 which was the whole concert debacle. So I'm that regard slow burn is putting it lightly. A slow burn is t necessarily bad if the author knows what their doing. A slow burn still has forward momentum.
I just don't know what's going to make me drop this first: the near stationary slowness of it, or the authors overuse of unnecessary drama.
But this is labeled as Girl's Love (They're just close/lifelong besties, any perceived lesbianism is purely headcanon on the readers part) and not yuri (They're lesbians, and most definitely physically attracted to each other. Romance is generally pure and diabetes inducing with no outright depictions of pornographic sex required. #yuriisnotporn), so I feel it necessary to give the creator a breaking that regard.
I do understand the frustration though of trying to sort through the mess that is MangaDex's "Girls Love" tag, due to the rather archaic understanding of the genre, to get my fix. Girls Love, Yuri, and pornographic content should be better delineated from each other so people don't feel like there getting baited or that the creator is violating their "writer's promise" to the reader. But that's something outlets like MangaDex need to figure out. Not the author's problem to fix.