translator notes are one of my favourite parts of reading something foreign. it’s just a small trivia about something and allows me to understand the target culture just a bit more. this is way better than translators aggressively localizing some text to a comon american phase that will anyway make no sense to me.
tns get bad rep because lazy/elitist translators (i would vote the op is a bit more than being lazy) but they are a very important part and can be very valuable when done well
i’m happy to see The Summer You Were There mentioned in possitive light. i did enjoy it and while i don’t think it’s amazing i have read quite a lot of negative comments about it which i think are ungranted.
about manga recs, have you read The Moon on a Rainy Night? it’s probably my favourite teenage romance manga so i heavilly recommend it.
for LNs, “Adachi and Shimamura” is really good altough a bit slow teenage romance. there is manga and anime adaptation of it if you prefer the medium but both are behind by far