WordPress front-end user create list of posts wether logged in or not

I am in need of some advice/nudging in the right direction to achieve the following:

Users visiting the WordPress site will be presented with a list of artist profiles (these are set up as a custom post type).

The User will then be able to add/save the post to either a new list or add to an existing list called ‘User Projects’.

If they’re not logged in, they would be able to create a temporary list, with the ability to login and save it.

I have ACF Pro installed, and at the moment I’m using the ‘Post Object’ field to link the posts in the WP Admin, but I now need this to work on the front-end and without the need to be logged in to begin with.

Ideally this would all be done with an ajax button, allowing for a smooth user experience.

All help greatly appreciated.

Thanks!