Perhaps I will invest in some of those luggage vacuum bags to try and limit the linear dimensions as much as possible and attempt to travel with it

i’m not totally averse to flying (likely would be from Haneda if so) but sort of wanted to do the Shinkansen thing and maybe check out Osaka a little bit (have been to Japan about 100 times including the 18 months or so I lived there but have never been to Osaka other than the airport and train station)