Where do I begin on this journey?

Hello everyone! This is my first time posting on reddit for anything and I honestly didnt know where else to go.
I (32F) have been in a long distance relationship with a Japanese man (27M) for the past four years. In 2023, I took my first trip to Japan to see him and have been three times in total across these four years while he has come to see me twice with his third trip lined up for later this year.
We have every intention of remaining together for the long term and have been talking about the next step of living together.
Now, I am a renter here in Australia while my partner has family land and deep set roots. I've decided I will be the one to move internationally so we can begin building our lives together. I dont have much holding me to Australia as I'm not the most close to my family and I lost touch with my friends a long time ago aside from the few work based friends I've made at my current job.
Moving from one country to another I'm aware is a big thing and has a lot of logistics surrounding it. What I'd like some help on is those crucial steps.
I will have a place to live. I do not need to worry about housing.
As an Australian I can go on a tourist visa for 90 days before requiring to return to Australia.
Is it considered a good idea to go for those three months and spend that time looking for a work sponsor and/or study while beginning to also establish my relationship with my partner?
When it comes to language, I am extremely lacking. I'm currently taking weekly one on one classes with a teacher to begin learning words, particles, sentences etc. I know my hiragana and am working on katakana also. I am extremely interested in taking classes in Japan at a language school. Is this considered a good idea to enroll? Will they accept someone of my age and ability? And how much AUD would I be looking at roughly?
I will be living in an area of Tokyo and the train lines are very reliable so can travel as needed to surrounding areas.
I desperately need some advice and direction. I've moved interstate before and a lot of it was just winging it but this is different. Currently I have a timeline set to travel in September.
I greatly appreciate all and any advice.
Thank you.

by Exciting_Pizza3878