Just another normal working person
Author at least gave viable solution to it claiming his chakra was being automatically used by his body, But Haki Training and cultivation thing doesn't make sense. Imagine Boa hancock and ladies from Amazon lily using sperm to strengthen their body to awaken haki. Haki is ambition and manifestation of will nothing to do with body being strong to awaken it. Aisa was innately born with it, koby despite being hundred times weaker than zoro in terms of training body, Awaken haki at Marineford. What Author is trying to do doesn't make sense.
I understand you want to write matches but as a reader there is little to very less character development of kazuki outside football. Pitch in some breather chapters to develop his character. interaction with fans, social media. Sponsored ads daily life. kazuki should not be football playing robot.