I read their documentation yesterday, and it strongly advised a complete reinstall. While they do have a tool that eases the process of storing your setup and then recovering it on top of a new install, it’s still significantly more complicated than just ‘sudo apt upgrade’.
How are these industry-leading policies when Fairphone, a much smaller company, is promising 5 android updates and 8 years of security updates? And it’s not like Fairphone doesn’t have a good track record AFAIK.