I doubt anyone alive now is aware of the whole truth given that it takes place 200 years ago in a politically turbulent part/era of the world.
We see errors/lies in articles about current verifiable topics all the time, surely history from hundreds of years ago had even less fidelity.
It's more about historical inaccuracy overall. I think Napoleon in particular has an analysis on A Collection of Unmitigated Pedantry [1].
[1] It's not a proper analysis like he's done for other movies, but here it is: https://acoup.blog/2023/11/17/fireside-friday-november-17-20...
We can't know the whole truth but we have enough quality data about ancient rome from multiple angles to know "gladiator" probably shouldn't be our first lead on the matter.
It would behoove everyone to never take movie representations of history as fact, even if the broad strokes are supported by evidence.
That's not the read I get on the man from my reading, so I found it very disappointing from a historical perspective.
From the "is it fun to watch" point of view... it was middling for me. Some of the battle scenes were cool, and there were some funny lines throughout that made me laugh, but overall as a story I found it pretty uninspired. Like, Gladiator had tons of historical inaccuracies as well, but it stood on its own as a really fun movie to watch and I can't put Napoleon in that category.
It's hard to imagine that this was an accident, since Scott clearly took great care to portray Josephine (an aging, black-toothed, capricious bimbo whose thoughtlessness was regularly a problem for Napoleon) as a young, beautiful and strong woman who was apparently "cleaning up after" Napoleon.
I got the distinct impression of a British director gleefully taking ole Boney down a notch.