You cannot directly remove individual subscribers from your YouTube channel
You can block a user to stop them from interacting with your channel
Open YouTube Studio
Go to Settings
Select Community
Add the user to your hidden users list
Use the channel’s comments or community moderation tools to manage unwanted users
If needed, report the user for harassment or policy violations
You can make your subscriptions private, but this does not remove subscribers from your channel
You can delete your channel to remove all subscribers from that channel