Not necessarily.
If you have 2 pumps, they need to both be pumping the same liquid, at the same speed, same pressure, they must be working absolutely in sync with each other.
If one is running even a little bit slower or faster than the other, then there will be a lot of presure on the other to keep up, and of course that also means that the first one is then having to work that much harder because of the weaker one.
I am of course being completely inorant in saying this as I honestly dont know, however, I will admit that in my house, in the radiator system, as the house is quite big and tere are lots of rooms, I do in fact have 3 pumps that pump the water hrough the radiator pipes etc, but I alos know that one one is in control, the other 2 are merely slave pumps.. again, showing my ignorance, I dont truly know how that works... I can imagine but if its how they are doing it, I dont know? - Maybe a PC cooling setup will be the same?
But the pump in an AIO system is only a tiny little thing, while a proper pump is a great deal bigger and surely stronger and will be able to take a great deal bigger setup surely?