Theorycrafting on best way to learn Japanese output (speaking and writing)

For some background, I've taken around 500 hours of speaking lessons now via 1-on-1 internet lessons, spent about 1 year total in Japan (for vacation though, so not too much exposure), and passed JLPT N2.

I have 2 separate areas of learning I would like to get some advice on for other upper immediate or advanced learners who either do or don't take speaking lessons.

First one is grammar, I still find myself making the same basic grammar mistakes after 500 hours. Maybe due to lack of specific practice. It would be cool if there was some way to aggregate all grammar mistakes, sort by most frequent, and then drill down specifically on those ones. Maybe a site where you can free-chat with AI or something via text and it aggregates your most common mistakes and you have to practice those. Maybe a bit advanced, but you could also theoretically upload a whole video and have some tool map out your mistakes and aggregate them over time.

Second one is regarding vocab. Every hour speaking lesson, there's at least 30 words that I learn, and also specific context that I need to add. Do folks generally SRS these and how do you incorporate audio and context? I used to do 1-word SRS, but I don't like doing that anymore because there's no context and audio. Is there a fast way to get context and audio via some AI tool?

I myself work in tech and wouldn't mind working on something like this as a passion project, but not sure it would cater to wide enough of an audience since it's mainly useful for advanced learners. (also wouldn't want to reinvent the wheel of course). The new AI speaking apps I've used quite frankly suck and are not good for advanced learners.

Would appreciate any advice or resources here or what folks think they would want! Thanks!

by smart_guy12347