Child of Japanese National Visa vs Passport?

I am 26 years old and have a Japanese mother and British father. I was born in Japan but have been living in the UK for the last 20 years or so.

I left my job recently and wanted to spend some time in Japan - around one year. However, I do not possess a Japanese passport (I did not renew it before turning 22).

It seems I have two options: Apply for a Japanese passport or get the child of a Japanese national visa.

Having a passport would be ideal but I know Japan does not recognise dual-citizenship so this may not be feasible. However, I've read some accounts of people in similar situations managing to get passports after failing to renew.

The other option I have is to get the visa. I feel like this is the more sensible route but I'm slightly worried it could somehow make it impossible to get a Japanese passport in the future (most likely won't need one, but I don't want to burn any more bridges, already regret not renewing my Japanese passport like so many others!)

I don't really see why taking a 'child of Japanese national visa' would make it more difficult to get a passport, but as the whole granting of visa and passports is deliberately opaque and random, it is possible. As for the option to chose a Japanese passport, can you afford to lose your UK passport?

I'm sure you're aware but on your UK passport you can already stay for 6 months (3+3 months), would two separate 6 months trips to Japan do the trick without getting the visa or the passport? You wouldn't be allowed to work.

since you are a Japanese, you have to enter Japan with Japanese passport.