Hi Allison,
You are not obligated to give him your phone number this soon. You only just met each other on a dating app. It’s alright if you want to take more time to get to know him better online before divulging your phone number.
Let him know that you would much rather get to know him better online for now. If he is truly interested in getting to know you as a person, he should agree to this.
If he still demands or pushes for you to give him your phone number, he is clearly disrespecting your boundaries and that alone should let you know that he wouldn’t be a good candidate for potential romance.