Book 6/season 6 is the end of the "original" Expanse; book 7 takes place decades later. If they want to make books 7-9 into Expanse: TNG they might want to recast the actors. Personally I wouldn't mind seeing the novellas made into pseudo-standalone movies.

Rumor is that is exactly what they are planning. A clean "break" at the show level and doing it as two "separate" shows would help simplify marketing and budgeting and contracts, especially with a recast.

This makes perfect sense to me. A time-skip of several decades would be tough to pull off.

I don't see an issue with using the same actors, people seem to live much longer lives anyway and some make-up will make them look older. I really want to watch the last three books as a big budget series. Jeff, if you're reading this, you should have the time and money now to make it happen. Please?

Blue Origin launching a streaming service would be so 2021.

Expanse but actually shot in space

Some of the novellas were actually part of the show.

Canceled it, then resigned as CEO, he knew what he was doing