In TNG, we see multiple sub-eras, @CoolRockSkii…
(ignoring future timelines)
Missing Years (which include up to about 2350, based upon uniforms)
TNG proper -
Borg War on
Dominion War on
We see small changes to issue equipment styling: TNG season 2 or 3; DS9 dominion war.
We are told the Galaxy class is not only relatively new at start, but also significantly better than older vessels.
We are told also that the Defiant is cutting edge when DS9 gets it.