I’m sorry to hear you’re having trouble keeping the LSCache plugin permanently deleted.
To clarify, LiteSpeed is not responsible for auto-installing the plugin on your website. This is a hosting-provider-level issue.
If your hosting provider is using the LiteSpeed cPanel tool, you can opt out of future updates this way:
In cPanel, choose the LiteSpeed Web Cache Manager, select LiteSpeed Cache Management > WordPress Cache and “flag” your site. This will make sure your site is skipped next time the mass installation tool is run.
Otherwise, please contact your hosting provider for help.