<I wonder if a cease and desist to their legal department would work better?>

I assume you mean the LinkedIn legal dept. The problem there is that these companies are so big that a 'complaint' or 'cease & desist' to them would be like a mosquito bite, if that, & most likely get lost in the 10s of thousands of other complaints.

It's the same with FB & Insta, etc. One of my daughters had a FB acct taken over that she had accumulated quite a following (~100k plus) with her custom hand drawn artwork. It was impossible to get any acknowledgement of the issue let alone get a suitable solution. And, unfortunately these large companies do not care. Sometime makes you wonder if LinkedIn & the like are even worth it