@Shalia - Gad that you were able to recover! To my knowledge, I don’t think you can technically recover a List that was deleted. You can recreate the List, and then manually repopulate them. However, as you’ve found, the profiles of members of a Deleted List are still in Klaviyo (Unless you use the Klaviyo Maintenance process to Delete Profiles).
So in a bit of a coy answer, maybe there’s no real reason to Delete Lists - keep then around forever. Klaviyo doesn’t charge for having multiple Lists (only the amount of Profiles and Volume of Emails Sent). In other words, if you have 100 unique Profiles, and they are in 10 different Lists, you are still charged for 100 Profile even if some Profiles are in multiple Lists.
Additionally, you can build Segments of your List, so you don’t really need to modify your Main List at all. If you need a temporary audience, a sample of the audience, or a Segment based on certain events or custom properties of that audience, the best practice is to create a Segment from that List. Unused Segments automatically get Archived after some time so it does help to de-clutter the amount of Segments and Lists.
Hope this helps!