Notable from his absence on that list is Jeremy Renner. William Brandt didn't return for Mission: Impossible Fallout because of Renner's responsibility with Marvel's Avengers movies.

Why did Brandt leave Mission Impossible?

The character appeared in two movies then disappeared without a trace. ... “Jeremy had his commitment to Avengers, which ironically they ended up not exercising, and we didn't know what the [sixth Mission: Impossible] movie was, so we couldn't provide a schedule. We needed absolute freedom.

Will Jeremy Renner come back to Mission Impossible?

Jeremy Renner is not confirmed to return in Mission: Impossible 7. Renner made his franchise debut as William Brandt in Mission: Impossible - Ghost Protocol and was thought to be the future lead of the series.