>>51348715The problem with Giovanni is that he wasn't the Champion or former Champion, and he was just a Gym Leader, which in some ways implies that the rest of the League recognized his strength, but that he wasn't good enough to be part of the Elite Four, which says a lot already.
As for the three losses, you can chalk the first one up to him just on an off day and not using a proper team, hell you can argue the second one to that extent, but even then that is pushing it. Giovanni just doesn't come off as a strong trainer in terms of actual gameplay, and to some extent the actual lore. Sure he's a powerful trainer, but he still gets beat by children and isn't good enough to be in the Elite Four. The only way he really shines is by having multiverse shenanigans where he can do as he pleases ultimately if it doesn't work out in one timeline.