Thanks for sharing your struggle. I don't know what I could suggest here as an answer to this. Sadly, from what you wrote, it doesn't sound as though there is an answer except, as you mentioned, to simply leave & go make a life for yourself on your own. I know how difficult that may be for you. But otherwise, I fear, you're simply stuck living the life you're living as long as your mother is living. Here are links to some articles, from PsychCentral's archives, on the subject of how to deal with difficult family members as well as others:

https://psychcentral.com/blog/how-to...amily-members/

https://psychcentral.com/blog/whats-...deal-with-one/

https://blogs.psychcentral.com/careg...-toxic-people/

https://blogs.psychcentral.com/careg...eed-to-escape/

https://psychcentral.com/blog/how-to...itical-people/

https://psychcentral.com/lib/10-way-...er-boundaries/

My best wishes to you...