There's much to like about this, though the slowness is severely debilitating.
I ended up digging the story, enjoying the cast and becoming interested in the characters but the extremely slow, one of the slowest paces I've ever seen, nature of 'Theatre: A Love Story' just significantly overshadows any positives feelings I have for this unfortunately.
It's 2hrs 15mins and I felt every single second, by the end I felt like I had just watched a 3hr+ movie. And that sucks, because I came close to enjoying it. Kento Yamazaki and Mayu Matsuoka are very good, I am more than open to seeing more of their respective works.
As I type this my instant thoughts about this 2020 flick are actually positive, but I can't let the pacing issues slide sadly. Worth a watch, despite my feelings I'm not surprised to see others love it - each to their own, as always!