For me it would depend a lot on things like -
Are you exclusively dating or still seeing other people?
Were the 4 dates all evening/day or just an hour or so for a coffee and a chat?
How quickly is she replying to your messages and you to hers? If she’s taking a long time to reply she could be playing games and making a point about how long it’s taking you, or she could be busy and not really want more contact, but it would be useful to know which for future reference!
The best thing would be to ask her. Next time you meet in person just say that you enjoyed the gif/photo/message she sent you this week, it makes you smile when you get a message from her or something, and say you want to see how she feels about texting/calling in general, whether she prefers texts or calls or FaceTime. How often she’d be comfortable etc.
For me with my Ex he would prefer calling and I hate the phone, so would prefer a text as I can answer when convenient. He’d always call in the middle of me cooking dinner or something, and while it was nice to hear from him, I knew it was because he was driving home, so it was a good time for him, but annoying for me. Sometimes I would text him during the day, and not hear back until 11pm or so. That pissed me off. You haven’t had 30 seconds all day or evening to send a reply, seriously?!
So it’s good that you’re curious about finding the right level. But honestly people are all different so the only way you’ll know is by asking her.