I think One Piece speed is a bit inconsistent. Lightspeed would be able to travel around the globe 7 times within a second. Yet, for example, when Kizaru fired his Yasakani no Magatama from mid range against Whitebeard, Whitebeard was able to comment on it, saying how bright it is, which would be physically impossible, unless Whitebeard speaks like 10 times the speed of light. We had Zoro dodge a light beam from close range pre TS, we had Sentomaru simply outrun Yasakani no Magatama, etc. Even Law's submarine avoided a barrage of lightbeams swimming around them, and I doubt a submarine travels faster than lightspeed under water.
So Oda doesn't really seem to be consistent with speed. In Naruto on the other hand, Kishimoto paid attention to making it realistic, with A being seen to outspeed an Amaterasu that in slowmo spawned instantly before him, not even travelling in the first place.
So I think it's less that random OP characters run around at lightspeed, but that Oda doesn't take it serious.
So Oda doesn't really seem to be consistent with speed. In Naruto on the other hand, Kishimoto paid attention to making it realistic, with A being seen to outspeed an Amaterasu that in slowmo spawned instantly before him, not even travelling in the first place.
So I think it's less that random OP characters run around at lightspeed, but that Oda doesn't take it serious.
Whatever the case shouldn't you at the very least should accept that their speed department is matching 8G-Guy? At least for Shanks, Kaido, Mihawk, and Luffy? While Linlin's flight speed should keep up with Juubito?

