Hi Adrian, I am John J.D., a fellow Microsoft user like you.
I understand you're having issues removing devices in the Phone Link app. I'm here to help. You can remove devices by going to the Phone Link app, clicking the Settings (gear icon), selecting "Devices," finding the devices you'd like to remove, clicking the ellipsis (...) to open the menu, and then clicking "Remove."
Should you need further information please let me know.
John J.D.