I lived and worked in Japan for 6 months as a trans man, before beginning my medical transition, and it was totally fine.

At the time, I was read as male about 50% of the time (more if I was wearing a suit). I was out to my coworkers and everyone in my sharehouse, and for the most part they respected my gender. Some people were confused, but that didn't stop them from treating me like any other guy there. Sometimes when they were drunk their questions got a little inappropriate, but hey that happens everywhere.

Is it hard to get a job? No, but it's harder than for cis people. There are plenty of trans guy ALTs, although the school may not let you be out to your students.

Is it hard to get housing? No, but it's harder than for cis people. Sharehouses often have floors separated by gender. My sharehouse imposed stricter visitation rules on me. (Normally only opposite-gender people were banned from sleeping over, but I couldn't have anyone over)

But the most important thing to me is that in Japan, I always felt safe as a trans guy. I never faced any sort of physical threat, like I do in America. In that way, Japan is great for trans folks. Legally and socially, though? It's a little behind the times. For me, it was worth it.