Are all grandmothers like this?

I’m in my mid 20s, living with my long term partner. My family loves him. My grandma is 73 and she’s always treated all of us (including my mother, 54) as if we are 10 year olds.
She’s the most wonderful helpful woman I’ve ever met. But she’s extremely nosey, she goes through our things any chance she gets.
Today she was over visiting and I turned my back for 2 minutes and she had somehow unlocked my phone and was reading my boyfriend and I’s texts.
She chased me around my own home trying to spank me for having sex.. Then asked me insanely inappropriate questions regarding birth control, how often we do it, etc

After she calmed down I asked her to stop going through our things and that I didn’t want to hurt her feelings but I was trying to set much needed boundaries with her.
She laughed at me and said “boundaries? Who ever put that in your head?”
As if I was a child spouting nonsense I heard off a movie….
It was all to much for me. I’m not really sure how to deal with it. Any boundaries any family members try to set with her she completely obliterates.
She refuses to accept that anything is wrong with this behavior.
Has anyone else experienced similar situations and know how to deal with them without hurting feelings or burning bridges?

Updates
+1 y
After a very calm talk with my grandmother. She apologized for the attempted spanking.
However the boundaries conversation took a different turn, her response was
*laughing* “I’m you’re grandma, not a stranger. I should be allowed to poke through your house every once in a while. And if you have a problem with that then you’re hiding something you’re not supposed to be doing.”
I’m really unsure of how to go about this.
Updates
+1 y
As for the baby discussion. We aren’t actively trying but we would be happy if it happened. But I most certainly wouldn’t be letting her take care of it or even babysit.
Aside from her and my grandfather, I am the ONLY one in the family who isn’t on drugs and doesn’t have an alcohol problem so I would think she wouldn’t see me as irresponsible as she does
Are all grandmothers like this?
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