The original film also made some pretty significant changes to the Freddie Mercury timeline for dramatic purposes, changes that would then have to become part of any sequel.
Bohemian Rhapsody covered a lot of ground chronologically speaking, a lot more than a sequel would have to work with.
Turning the rest of Freddie Mercury’s life into a second film may be a bit harder than simply picking up where the first movie left off.
This would likely make the follow up significantly more historically inaccurate, since it would have to assume things like Freddy’s AIDS diagnosis was known to the entire band for years.