According to signal facts all the have is your phone number and and the date you signed up for the service and the last day you connected to the server. IP address are not logged or stored the do t have access to it and signal has said this everytime the get a warrent for user data. So yes it is possible to have a secure service that doesn’t collect IP addresses but yes the do have some limited data so you are correct.
Very good and true point well said I agree with you on that good thing I am not important enough for it to be a issue lol or do anything illegal.