I've said it before and I'll say it again. If Gunn wanted to sunset the old DCEU, they should have done it gracefully after the previous management told Cavill to announce their return, as there are many who do not have a problem with Cavill, only their version of Superman - that let's face it, was not theirs to control - they're just the actor. And whilst it may not have been Gunn who was in charge at the time that told Cavill to go announce their return, Gunn could have given the DCEU one decent swan song out gracefully (MOS2 or equivalent). Allowing Cavill to step down gracefully out of the Superman role that's been recast for the new DCU and get DCEU fans to follow on to the new DCU.
Instead, they chose the current set of events that lead to now. And hence the schism of the Superman fandom when it really should have been a real "Vocal Minority" that doesn't like the change, we now have large groups at odds with how things are instead of most of them satisfied Gunn has allowed their previous Superman to have their goodbye and get ready for the new one.