Open YouTube and sign in to your account
Go to your profile picture
Select YouTube Studio
Click Settings
Click Channel
Open the Advanced settings tab
Scroll to the bottom
Click Remove YouTube content
Sign in again if prompted
Choose to hide your channel content if available
Confirm the changes
Set your subscriptions to private
Go to Settings
Click Privacy
Turn on Keep all my subscriptions private
Set your liked videos to private
Turn on Keep all my liked videos private
Set your saved playlists to private
Open each playlist
Change the playlist visibility to Private
Limit who can see your activity by avoiding public comments and public subscriptions
If needed, create a new channel with minimal public activity