The film is generally distributed in North America through GKIDS and they have a strong relationship with the HBO Max service.
Check out our review of the film from its Anime Expo 2019 debut and our Blu-ray review.
That has them now bringing the film out there where it’s available in both its original Japanese language with English subtitles as well as the English language dub. you can find its series page here.
Hiroyuki Imaishi directed it working with writer Kazuki Nakashima while Shigeto Koyama worked on character designs and mechanical designs.