How do you deal with being treated like a horrible person when you are busting your butt for someone who can't take care of themselves?

I feel sad for your MIL having a stroke, but her behavior is not ok. It is difficult losing ones independence, maybe she is angry not at you, but the circumstances. Try talking to her and explain you are doing your best and would like to continue, but you need more cooperation and less complaining. Wow you are a good DIL, some would not do what you are doing. Has your MIL always been this way or is it her illness the stroke and dementia? Are there any other family members involved? Maybe a consult with her primary doctor is in order. She may need a medication to calm her. You are certainly not a horrible person in the least. She is so fortunate to have you and if things do not turn around, I would search for a decent facility near you. Your health is at risk from all the stress and turmoil.

Where is your husband/wife in all this?

First, understand that this is normal behaviour in a person suffering from Dementia. You can no longer reason with them. They process much slower and can't comprehend. If she was this way before, Dementia tends to make it worse. Think of her as a small child. She can no longer appreciate or show empathy. Her brain is broken, as some members call it, me I say its dying. She will never be happy. Don't feed into her demands.

She doesn't have to go anywhere. You have already found she is not happy anywhere she is. So don't worry about moving her anywhere else until her Dementia gets to the point she needs more care than an AL can give or the money runs out. Then Medicaid can be applied for.

If MIL is in an AL, then I assume you haven't been able to visit. Some members have seen this as a blessing. Its given them time to take a breath. You may need to just step back. If your visits seem to get her going, then don't go. Does she have a phone? Are you the only one she calls? At this point, since no one can visit I wouldn't take it away since its her lifeline. But if the calls she makes are just to complain to everyone, I would lose it when the Facilities reopen. Make sure you tell the staff you took it. You can ignore her calls. Let them go to VM. I use "Do not Disturb" on my phone. Only way I can set it up to only allow calls and texts from my contact list. I would take MIL off my CL. The call will go to VM and you can deal with her when in the mood. Or block her and you don't know she even called. Then you call her maybe 1x a day to see how she is and what she needs. When she gets started, just tell her time to go and hang up. There is no more trying to "condition" them or make them understand.

YOU WILL NEVER MAKE HER HAPPY! You have to come to this conclusion and stop trying to. And that is OK. Its OK to say I can't do this any more. The ball is now in your court.