Trying to get a mortgage in slightly unusual situation

I'm a foreigner on a 1 year spouse visa, married to a Japanese citizen. My wife is a 正社員 and I'm self employed. My wife is also on maternity leave (see post history) but will return to work soon.

We can put up 20%-30% as a deposit. We both take medication for mental health conditions (depression and ADHD).

We tried talking to local banks but without PR they said we couldn't get a mortgage together. We are going to continue trying with other banks. It seems like it's a bit of an uphill struggle given our situation. Originally I thought I would wait to try to get PR but it seems like that could be many years in the future. Is it relatively easy to remortgage after getting PR? Which banks should we try? Has anyone else had experience getting a loan in less than ideal conditions?

by BassTyper