I once tried to divorce Facebook. I couldn't (nobody can).
Not even a judge can force it - there are no grounds for incompatibility, physical or mental cruelty, adultery, bigamy, blashpemy, pornography, execution, you name it . . .if you make the mistake of signing up (which I did) you are stuck forever on the human hamster merry-go-round of misery.
I can confirm that is against Upwork policies to include a link to your LinkedIn profile in your Upwork account as it is considered contact information. However, linking your accounts through the option in your Settings will help the system provide you with more specific job recommendations and help your appearance in search.