Language school to meet vocational school entry requirements

Hi all. I (35F) am looking at enrolling at Hiko Mizuno's jewellery course but saw that there is an N2 language requirement and an interview upon application. I have previously studied Japanese formally and informally (150h under the local Nihon Foundation using みんなの日本語 in 2018 and Japanese lessons in Sannomiya church in 2003). I took an assessment test last year and am N5 reading and writing with a recommendation that I retake beginner 2 because of the kanji, but N4/N3 in comprehension/conversation. I do semi-regularly go back to Japan and am able to have conversations with locals at bars up to a point, read hiragana and katakana fairly quickly and know the basic 100 kanji, and have Japanese friends in my home country who I converse with in a mix of Japanese and English. I retain it much quicker when I am in Japan compared to when I am in my home country. I never studied it formally because I didn't consider going to school in Japan until now.

That said, how long would it realistically take to achieve N2, and what language schools would you recommend for getting into a 専門学校? I'm thinking of studying maybe 20 hours a week + 2 hours of homework is the most comfortable range for me as I would have to work part-time while there. Ideally I'd like to apply for Hiko Mizuno in 2027, so a year of language school. I would also need visa sponsorship and assistance.

Upon research, I have seen mixed reviews for Akamonkai and KAI but would like feedback regardless from people who have, or know people who have, attended these two schools. I would also like to know your thoughts on ARC, Yamasa, KCP International, and Nichibei Language School, but any other suggestions are welcome! I would like to stay within the Tokyo/Yokohama area (yes I know Yamasa is in Aichi but hey consistently good reviews are a good sign!), with second preference being in the Kansai area unless the school is really that good haha

Of course if anyone also has feedback regarding Hiko Mizuno's jewellery course I would really appreciate it!

Thanks everyone!

by hysterionics