It's worth noting that the way Signal's architecture is set up, Signal the organisation doesn't have access to users' phone numbers.
They technically have logs from when verification happens (as that goes through an SMS verification service) but that just documents that you have an account/when you registered. And it's unclear whether those records are available anymore since no warrants have been issued since they moved to the new username system.
And the actual profile and contact discovery infra is all designed to be actively hostile to snooping on identifiable information even with hardware access (requiring compromise of secure enclaves + multiple levels of obfuscation and cryptographic anti-extraction techniques on top).