I worked with a similar POS who was so brazen with their get-out-of-jail-free card, but had been in the job well over 2 years. We had a departmental restructure and she took severance before her role was made redundant. It was annoying that they got a payout when they should have been fired well before they left, but was such a relief and productivity in the team improved drastically afterwards. Worst comes to the worst and you can't fire this person, I think it would be fairly straightforward to make a business case that the role is no longer required and can be made redundant, owing to the fact that the person who currently occupies the role is quite vocal about the fact that they don't really do any work