You cannot directly remove a specific subscriber from your YouTube channel
You can hide a subscriber from your public subscriber list if they are subscribed publicly
Sign in to YouTube Studio
Go to Settings
Select Community
Open the Hidden users tab
Add the channel name or user to hidden users
Save the changes
To stop someone from subscribing again, block their channel
Open the subscriber’s channel page
Click the More options menu
Select Block user
Confirm the action
To remove all subscribers from public view, set your subscriber list to private
Go to YouTube Settings
Select Privacy
Turn off Keep all my subscriptions private if needed for your own subscriptions
For channel subscriber visibility, use the subscriber privacy settings available in YouTube Studio if applicable