I want to find an IT Job in Japan before I finish language school in April 2028. Any advice?

I'm currently living off savings in Tokyo, and they should last me until the end of language school. I haven't actually applied to any jobs yet because I still haven't made my 履歴書 or bought a suit for the interviews. I am focusing on passing the N2 this december and hopefully if I'm successful, I can aim for N1 next December.

I wish to find an IT position in Tokyo, but if I get an opportunity in another city, I'd be happy to relocate. I have 2 years technical integrator for a credit provider, and 4 years of experience working as a programmer in a bank. Issue is that in my last job, we used incredibly old, specialised and obscure banking technologies (Java 8/Temenos T24) so my skills are not really transferable. I probably have to start from the beginning as a Junior if I want to be a programmer which is probably a gargantuan task. I also have experience with Python, SQL (PostgreSQL, NOSQL) Linux (Fedora, Mint, RedHat), Spring, NodeJS, SOAP/REST APIs (XML, JSON and PHP).

I also have a BSc Computer Science (2:1 with Honours) from the UK.

So yeah my skills are kind of all over the place and I want to focus on my Japanese before I start going for IT positions. I'm just curious, what are the most sought after skills that I might need to focus on for IT job hunting? It doesn't have to be programming, I just want to find a job willing to sponsor a visa.