Need advice about parent's behavior

I'm reaching my wits ends and not sure what to do next, if anything. For context im in my 30s, female, the oldest child and my mother is in her 60s, also an oldest child. I moved away from home in mid 20s and live about 2 hrs away.

I'm having an issue with what I perceive is her being rude and immature in how she communicates to me. 

We used a messaging app to keep it touch and recently switched to a different one. I decided years ago that text is the best way to talk to her for my own mental health. Pre pandemic i was visiting every 2 months. Now I try to stick with just major holidays unless something comes up.

The old app we used before allowed for messages to be deleted but didnt say so in the chat. The app would lag out and I could still see some of the messages in the notification or when I open the app.

The first few times she posted/deleted I mentioned it like 'oh I think the app glitched and your message is gone, but anyways moving on' or 'hey i think i have to reinstall the app because it said you posted a message but i dont see it'

I was hoping to give her an out that I could tell what she did but I didnt want to cause a fight or embarrassment but she didnt really acknowledge it. 

The other give away is there would be a sound notification of a new message but then nothing was there when I checked.

The messages would be negative and emotional implying I dont visit enough and implying that I think she is a bad mother or awful person. 

She prefers the way older instant messaging sites worked where the people chatting were tied to their computer so the conversation was going in the moment. I think she really hated it when I got a smart phone and could be responding to her as I went about my day and it could be minutes to hours later when I responded.

When I was a teen I typed up messages venting my feelings in messenger, then instantly deleted it from embarrassment. My friends would call me out saying it was rude, the give away back then was 'user is typing' and so they'd know I had planned to say something but then didnt. So the post/delete thing is like ten times worse because she took the time to type that all out, actually decided to hit send knowing I might have seen it and then rather than own up to her thoughts and feelings like an adult she deletes it.

With the post/delete behavior I started to feel a bit gas lighted by her.  

I began to feel guilt, dread and anger when I heard the notification beep, especially if there were multiple in a row, because if I didnt rush to pick up the phone and see the notification preview I was missing whatever she said before she decided to delete it. 

She is also on a different schedule than me she gets up at like 3pm and goes to bed at like 7am. So I would be woke up by the notification pings in the middle of the night. 

Once we switched to the new app it says the message was deleted that we can both see, it even has a time stamp, yet she is still doing it!

The new app doesn't show previews of the messages so I cant gleam anything from that anymore. I feel stupid for how vindicated I felt when I had visible proof she is/was doing this. 

Im just going to add that obviously my mom and i dont have a healthy relationship. She didnt have one with her mom either and I have empathy for why she acts the way she does, but its been years and I dont know how to deal with it. I dont want to deal with it anymore. 

I've even thought of asking an Ai to generate something I can send to her thats written objectively, without judgements or too much emotion because every time I build up the courage or get frustrated enough to want to address this, I just get depressed and sad.