A warm welcome here in the Roku Community, @rIckp23!
Thank you for reaching out, and I'd be happy to provide further information about connecting your Xfinity Flex to your TCL Roku TV.
You can connect your Xfinity Flex streaming box to your TCL Roku TV via HDMI port. Please also know that you may directly access the Hulu and Peacock channels on your TCL Roku TV by installing it and signing in to your existing subscription account.
If you can't access these channels directly on your TV, kindly visit this support article to help solve a playback issue.
Let me know if you have further questions or need any assistance.
Best regards,
Carly
Carly Y.
Roku Community Moderator