Japan custody: father blocked from infant — what have people done that actually worked?

I live in Japan. I’m the father of a child born in October 2023.

I’m still legally married to my wife, but we are separated. I have not been allowed to see my child for months. I have a lawyer, but the process is slow, and the other parent refuses to negotiate, delays, or ignores everything.

I’m trying to understand what actually works in practice in Japan when enforcement is weak and one parent simply refuses contact.

Some relevant context (kept as factual as possible):

• The other parent has a documented mental health history including psychiatric hospitalization and suicide attempts.
• There was domestic violence toward me in the past (including hitting and one incident where she threw a knife at me). The last time I was able to see my daughter my ex kept hitting me while her mother was present.
• To be clear: the DV and the most extreme incidents happened about 1.5 years ago, before separation. Since separation there has not been physical violence.
• I have recordings of some of the past incidents.
• The other parent currently has very limited income and has even asked me to help her get a lawyer. However she lives with her parents too.
• I’m concerned her mental health issues may be used as a way to delay indefinitely and justify continued refusal of contact.
• She has a very strong need for approval from her mother, and I suspect family dynamics are influencing the situation.

Also relevant: my visa is valid for a while and I am legally in Japan. I don't hate my ex wife and I don't want revenge. I’m trying to regain contact with my child and make sure my child is safe and stable.

What I’m asking for:
I only want to be able to see my daughter. I think custody would be better not because of my attachment to my daughter or any pride but because I am more stable than her. The problem is that the courts can make all sorts of demands of her but if there's no real power behind it she's not going to do anything. So what I need to know is are there ways of increasing pressure?
The problem is that if I go through the courts by themselves it's going to take too long and then they're going to just say that my efforts will be disruptive and ruin continuity. I think image is way more important to her and her family than money.