Hi. Sorry you’re experiencing this.
Please reference TEC Manual Updates (what you’ll likely need to do, except for The Events Calendar core/free plugin)
Or, you could just delete The Events Calendar plugin via wp-admin > Plugins.
Deleting The Events Calendar or its add-on plugins will NOT delete any of your data if you delete it via the WordPress plugin manager because that’s how we’ve decided to code our plugin.
FYI: deleting any plugin via FTP or cPanel’s File Manager (i.e. deleting just the files from the server) will also ensure a plugin gets deleted (if you delete the entire plugin folder) without removing any data from the database. This can sometimes be helpful to know in cases where a plugin does run an uninstall routine to delete data (again, our plugins do not run such a routine at this time and probably never will).
You can also see the difference when you click to delete a plugin, like this.
Please let me know if you get TEC core updated successfully.