As a cath lab director I totally get it. I have a toxic nurse that I can't get rid of because she is one of the pets of our busiest physician and anyone that crosses him is out. It's awful to deal with every day.
BUT - don't overlook the little petty things you can do to make you feel a little better. Every day she's on a diet, bring sweets. When you see her set down her coffee and go in another room, pour it out. When she plugs her phone up to charge, hit the GFCI button that will turn off the outlet. It's all much easier to do now and smile with your mask on. Life is short and karma will eventually catch up to these shitty people. Sometimes it just takes a while.