I'd say TNG got it's proper finale in "All Good Things" ...they just kept going, though.
The problem with AGT as a finale is that, while it's a belter of an episode to end the seven year run on, it's what we call an "open-ended finale". Because they knew they were going on to do movies straight afterwards, it had
to be that way.
They could wrap up
the show, but they could not provide closure
to the show. If that makes any sense?
But on reflection, this meant that the TNG movies were somewhat directionless. There wasn't anywhere else left to go with those characters, but they opted to limp on every few years doing new adventures with them anyway, retrospectively ruining the effect of AGT as a result.
The TOS movies still had places to go, because that show got cancelled and they all came back to the characters ten years later or whatever, meaning we could explore new aspects of all these people and how they interacted with each other.
By contrast, the TNG movies were always just some additional adventures taking place right after the series ended. Picking up right where AGT left off. They had no wriggle room left to do anything interesting
with the characters or their setting, apart from cosmetic details like giving Data emotions (which was quickly rescinded anyway), or blowing up the ship and replacing it with a new one (which didn't make a squat of difference to the actual stories).
One thing I will say for NEM is that it at least does have pretensions towards trying to provide some
sort of closure on TNG in a way that even AGT didn't. Even though a lot of that material was sadly left on the cutting room floor.