I personally regard the "giant Russian/Chinese/Syrian/Iranian" exercise reports as utterly false garbage, not just "unconfirmed."
The "report" (any other "reports" were just regurgitating the original nonsense) were from an previously-proven completely unreliable source (a semi-official Iranian news agency), described things that were pretty much operationally impossible, used terminology indicating a lack of knowledge of military matters, and of course they have all been denied by all governments mentioned.
The only reason people gave them credence was that 1) If it was true, it was exciting and scary and 2) it allowed people to indulge whatever their favorite End Times fantasy was.
Thanks - my BS detector had gone off for many of the reasons you cite but I wasn’t completely sure.