DrForinor I only have experience with two grinders — the Baratza Virtuoso+ (conical) and the DF83 (flat burrs). The DF83 certainly seems like it brings out the brighter notes in my espresso compared to the Virtuoso+, but I wouldn’t characterize it as being acidic in an unpleasant way. I can certainly set the DF83 coarse enough so that the shots are too sour, but going finer makes that go away without needing to do much else in terms of adjusting variables.
As a matter of fact, reviews of the DF83 consistently mention that for a flat burr grinder, the stock burrs seem to provide a lot of the richness and chocolatey flavors that are generally associated with conical grinders, even though the DF83 is a flat burr grinder. So there’s probably more going on than just a flat vs. conical thing.