Update [Sat 16th Sep, 2023 02:00 BST]:
During the latest Nintendo Direct broadcast in Japan, Hatsune Miku fans got another look at her upcoming Fitness Boxing Switch game. It's scheduled to arrive in this region on 7th March 2024. There's no word on localisation at this point in time.
Here are some additional screenshots from Nintendo's official website:
Original article [Fri 1st Sep, 2023 04:00 BST]:
Following the news earlier this week that the original Fitness Boxing would be removed from the UK eShop, developer Imagineer has now announced a brand new Switch game featuring the superstar virtual idol Hatsune Miku.
Fitness Boxing feat. Hatsune Miku Isshoni Exercise is launching in Spring 2024 in Japan and will allow players to enjoy boxing exercises under the guidance of the famous idol. Hatsune Miku's tracks will also feature in the game including her "main theme song by cosMo@bousouP".
You can see a brief teaser in the video above. There's no mention of a localisation, but a Fitness Boxing spin-off based on the manga series Fist of the North Star was released on Switch in Europe and America last year, so there might be a chance.