New Discovery season 3 trailer:
It seems like they're doing the Andromeda
thing where the galactic civilization of good guys has fallen and our heroes from the past must recreate it from scratch. It's also a little reminiscent of the cancelled Star Trek: Federation series concept, where the Federation has also collapsed (though gradually, due to stagnation and corruption).
Setting Discovery season 3 in the 32nd century is a smart idea, as it places it after the most chronologically recent events of previous series, which were 31st century (Daniels from Enterprise, the Voyager episode where a copy of the holographic Doctor is re-activated in a museum).
This means the writers of season 3 can still call on old lore, but the passage of time lets writers make significant changes to the setting as necessary. Perhaps more importantly, they can have any events take place without worrying about contradicting established canon, which was something fans complained a lot about.