I'm also someone who doesn't like texting very much, but understand that it might be the only way you can communicate with some people.
I think you did the most important thing which is communicate your patterns of behavior and boundaries. About their behavior you might want to consider that they might still text despite you desire to be alone without expecting you to answer immediately and understand that you will take your time - I do have friends that prefer to do this, but! If that brings you stress you can address that, and find a new middle ground.
But I’m just making an assumption without the full picture, if you genuinely does not feel safe and comfortable it's very reasonable to take a distance. You might want to be open about that just so they don't expect the same behavior from you, but I understand that can be very very difficult, specifically if they have a pattern of not listening to you.