This post is for @Nightmanhome . I found a work around to getting rid of those unlinked old devices. I removed them from my home and added them to a home I titled "Old Broken Apps". Honestly, I just wanted to stop seeing it. Then, I removed myself from the new home and "Deleted" the home. It was gone!! Hope this helps or that you finally found your work around.
For anyone else trying to unlink that old app, maybe it'll help you too. I finally stopped seeing an old "Hopper" from when we used Dish Network. Home wouldn't let me remove it because I wasn't "the owner", but no one in my house knew who was.
