you can hide these playlist with just removing a bit of code in file /components/com_muscol/views/playlists/tmpl/default.php
if you're familiar with PHP it will take just a few seconds.

Thank you I will look at that.
Is there a way to make it a override so I do not have ti upload it on every MC update?

can I just show the users own playlist and only their playlist when they sign in?
What I mean is, is there a my playlists menu item I could create?

well, if you modify the fiole I told you, it will actually become a "my playlists" type of page...

yes, you can override it using the joomla template system. that means, inside your /template folder, inside your template, in the /html folder you can create overrides. like this:

/templates/your_template_folder/html/com_muscol/playlists/default.php