I have a TCL Roku TV, and I added a Roku Stick to my account for another TV. It downloaded all of my channels and added them to the new device. Do I need to sign in to each individual channel on my new device or is there a way to sync those to the new device so that I won't need to sign in to them again?
It depends. Some may share a login across other Roku devices. Others will require a login. It all depends on how the developer wrote their app and what options they used with Roku. I assume login sharing may also require sharing more data with Roku.