Welcome to the Roku Community, @Clare65!
Thanks for stopping by. We'd be happy to share further information about this.
Please be informed that there is no other way to stream the YouTube app ad-free, as it requires a premium subscription to turn off ads.
You may also contact the YouTube Support team for further clarification and see if they can provide you with workarounds as they independently manage their app on the Roku streaming platform.
You may reach them here: YouTube Support.
Best regards,
Carly
Carly Y.
Roku Community Moderator