One dedicated circuit for each mono block?

If I have a dedicated 20 amp Circuit is that ok for two monoblocs? I read that a separate dedicated line is better for each amplifier. So the outlet can't have two plugs but it's better to not use one of the two plugs when connecting a mono block?

I have a transparent Power isolator which I know use to plug amps into.

So maybe a dedicated circuit can be used to plug amps directly into and then have Power isolator connected to a separate Circuit for everything else.

I am trying to evaluate the merits and to need for getting a second dedicated line while installing the first.