Where are you trying to save them? Is it in an app, or are you talking about the saved list that appears when you click What to Watch in the Roku main menu?
onn Roku 43" TV model 100012584 running version 12.0.0
Twenty plus years of online experience as a web developer, general user and consumer. Recording engineer. Sixty plus years of troubleshooting and problem solving in several fields. Here to help and get help when I have issues with Roku. Nothing more. Not here to socialize. That's what real life is for. 😉