Just be random with the school name. I'm sure a Random Name generator out there exists for schools

i looked it up and the name it generates are memes :p
tried to search up random cool japanese words and adding highschool at the end and there's actually a school with the name.i want something imaginary!

LOL. Now that would be an interesting school to attend. But still, I understand the need for something better. How about you just call the school something that reflects the story you're about to tell? If Google translate is to be trusted "Kaizen" is the Japanese word for "change for better" or "continuous improvement". If you want to go the more realistic approach though, then you'll have to think about the setting this all takes place in. Most schools are named after where they are physically located.

Just go with Shurimia Highschool