I have very similar issues and experience this disrespect constantly. It’s really makes you feel at a loss because our kids love their grandparents and the process of holding others accountable when boundaries are crossed feels awful… it’s worse when your kids get even older trust me….
You live with your mother. She's still treating you like a child because you're living under her roof. You can ask her to respect your boundaries, but it doesn't sound like it's going to change either way. You'll need to live independently to live the life you want... with the boundaries you want respected.
He’ll no!! Irregardless of your living situation you have that right as you daughters mom to set boundaries. Grandma should respect your wishes because in all reality if she cares about you guys’ relationship that’s a no brainer!!