We gotta keep in mind. When Saturn played punching bag everything was in control. He sent away almost all troops from the island without a second thought.
There was no broadcast countdown.
They had the strawhats surrounded.
He had an admiral next to him.
And he didn't even look much concerned having yonko and joyboy luffy in front of him.
So yeah, he really didn't care to show off, he already dominated the place. And constant Regeneration is a way of showing power and superiority.
Since the broadcast has started he's been quite serious. Venomous mini nukes and also easily evading a joyboy pizza move (that fucked up a logia admiral pretty much) are quite good feats.
We aren't even sure if one can block Joyboy's reality distorting attacks simply with haki as Meme and Kaido blocked Law's abilities. Kaido himself couldn't do shit about them for once.
The power distribution among the elders is probably very balanced. They all have equal status and authority after all.