For speakers of English, Japanese is supposed to be the hardest language to learn according to this authoritative source.
I can well believe it!
For 20 years I toyed with learning Japanese. I took a class briefly. I worked through some correspondence lessons. I tried to memorize kanji, phrases, and grammar rules. But it was all very painful. I just couldn’t apply myself.
Strangely, living in Japan wasn’t helpful; it became a hindrance. I picked up on the vibes there and became super-sensitive about making mistakes myself! And so I tried even less.