Limit speed on certain devices?

I have the problem that in my wlan are 4 laptops.

(Sister, father, grandma, me)

The problem is that the speed is poorly distributed,

e.g. From 400 MB / s I have only 2 because the rest have the other laptops.

Can you steer or share it somehow?

P.S. Have Unitymedia router

You can give priority to a device, then it is always the "first".

As?

In the router.

Yes, but where is it?

Internet / Filter / Prioritization

Have all possible settings in the router searched and hit on nothing with prioritization.

At Fritz! Box there's that. Which router do you have?

So from Unitymedia, but I do not know model.

Look in the manual, or googel for prioritization on your router.