I have unlinked my smart tv from one roku account and I’m trying to link it to my new account but I’m struggling to find anything that allows me to do that. I have checked in my account settings thru an iPad as well as on the tv. There is no place where it would ask me to sign in or anything else that would allow me to attach my new account to the smart tv.
To connect to a different Roku account, do a Factory reset.
Factory reset is accessed via Settings > System > Advanced system settings > Factory reset. This will clear out the unit's memory and you'll then have to set it up again as though it were a new unit right out of the box. In the process you can create a new account or connect to a different pre-existing account.