Routers are like cars. All cars have the same basic functions of getting you from point A to point B. Some cars are small and slow and can only hold one or two people. Some cars are large and fast and can hold 6-8 people.
Routers are similar to cars. Your internet depends on your router. Some routers transmit data slow, some transmit it fast. Some routers can support 1 connected device, some routers can support up to 15 connected devices. Your internet experience is extremely dependent on the quality of your router.