Fair enough. I don't agree that Snyder's movies are 'bad' movies in the least (especially not MOS), but I think there is some merit in your perspective - especially the part in bold.
As I'd said on the MOS thread over on the Superman forum, on some level, a lot of the criticism of MOS and BvS is rooted in ideological differences within the fanbase regarding the superhero genre and how it should be represented.
Yeah, that little speech by Keaton's Bruce pretty much set the stage for all manner of DC shenanigans, and every possible permutation of reboot/soft-reboot/retcon.
Its entirely possible to have the Peacemaker and SS characters on a completely different earth be entirely the same as the DCEU versions, while everyone else has changed. Gunn can pick and choose which actors from the DCEU he wants in his DCU. Kinda how how DC writers/editors pick and choose which past stories they want to include while building a new continuity.
The confusion of course arises from the fact that Gunn said the ending of Flash would reset the DCEU into the DCU, suggesting there was a causal link between the two. If we were to take that as face value though, then it would mean that George Clooney is the new Batman of the DCU, which is
clearly not going to be the case
And Gunn actively made the choice to get that new ending filmed...he could have gone with something different or simply gone with the original ending (which in turn would clearly cut off The Flash from his DCU).