>>280142231 (and other pics with that toxic message that enables obsessive self destructive behaviors)
Dat shit is only true in batoru manga and in real life when you was assigned with an important job under a tight knit deadline and don't want to get fired or lose an important match in any sports. In romance, the people who get what they want is actually those who simply doen't try, are assertive about his chances and is just himself, not those who bruteforce his feelings. Basically, the inverse to not giving up.
Besides, the flower metaphor in >>280142221 is a huge mislead because Kazuya was a stubborn fuck about the morning glory, and even though got the 1st prize for raising the most beautiful flower, in the end, it didn't even matter because the flower Kazuya grew wasn't the morning glory he wanted so badly.

What's Kanokari's ACTUAL message? 1: know your boundaries and your place, 2: just be yourself and 3: you can't buy love, you can't be captain save-a-ho and 4. Don't become obsessed, neither make useless efforts for someone you'll never get, better look around and you'll find out there are people who will love and care about you.

This manga is great because it deconstructs shounen tropes and shows the consequences of applying them to a realistic romance.

So after the spoilers...
Linkin park was right about Kazuya's efforts.
Now he'll go the "what i've done" and "numb" phases.