Other have pointed out that the house ("Y seats are set according to census data on population") and senate ("guaranteeing each state X seats") already do what you suggest.
Amazingly some guys thought it up hundreds of years ago. Is your issue that it is bicameral? If so what advantage would one house have?
> Other have pointed out that the house ("Y seats are set according to census data on population")
This is repeated all over this thread, but it is just no longer actually true.
The Permanent Apportionment Act means that it is only partially tied to census data. The low cap and guaranteed seats mean that low population states have more power per capita in the house to a significant degree.
Amazingly some guys thought it up hundreds of years ago. Is your issue that it is bicameral? If so what advantage would one house have?