1) What router do you have?
I have Verizon DSL. Verizon gave me a device that is:
3) wireless access point
all three rolled into one, I got 3 computers connected to it using network cable and 2 laptops connected wireless. I do not have any such problem you describe.
One more thing. I am not promoting Verizon DSL. The device they provided me at the time is not that great, for example, I can not set a password for my wireless network. Why? The device was made in China and the encryption technology is so important that it could not be provided to Chinese manufacturer because US government does not want Chinese government to have this encryption technology.
Life is short and dinnertime is chancy.
Eat desert first!