I am trying to extend the range of my home network to a garage about 130ft from my house. I buried a cat6, can plug the house end into my existing router, but need help on the garage end. In the garage I want to end up with the same wireless SSID as the house and also direct connect a smart tv. Do I need to use a switch before a wireless router/ap/range extender?
When used for 10/100/1000BASE-T, the maximum allowed length of a Cat 6 cable is 100 meters or 328 feet. This consists of 90 meters (300 ft) of solid "horizontal" cabling between the patch panel and the wall jack, plus 10 meters (33 ft) of stranded patch cable between each jack and the attached device. Since stranded cable has higher attenuation than solid cable, exceeding 10 metres of patch cabling will reduce the permissible length of horizontal cable.
If your existing router already have a switch part you should be fine
What you will likely buy is a router but what you need is a AP (true AP tend to be expensive because they include things like PoE). All routers can run as AP there is a sticky on this forum that tells how.
Because a AP is in effect a switch that has wireless ports on it your main router will control all the IP addresses. The SSID you can set to be the same or different it is up to you. There are advantages and disadvantages to both options. You should have a couple extra ethernet ports and if you need more just plug a small switch into the AP.