My Cookies directory is 11 MB. That's actually quite a lot, considering the length of the average cookie, but my disk is 256 GB and it's only gotten that big because I've been browsing for years literally without ever clearing my cookies and I can clear them at any time.

This is really a non-issue.

It is the user's session data. If it is stored on their end, they can choose how long they wish to store it for, and delete it any time they like.