Good ways to get a visa with part-time employment without much need for money?

Hi all, used to live in Tokyo and been thinking about relocating back for various personal reasons. I'm lucky enough to have built up pretty good savings here in the US, and could get by in Japan for quite a while on that, but I'd love to work part-time (I don't think I have a 9-6 5 days a week in me) while still being able to secure a visa. I have a good tech job currently (potentially looking into the HSFP visa as well), and have found a few leads online, but was wondering if anyone had advice on good industries for something like this or good sites to check? Are there Eikaiwas that hire folks on part-time while sponsoring a visa?

Thanks for your help!