Don't use messengers that ask for your phone number and aren't end-to-end encrypted. Use services that store as little data as possible. If data is stored, it can be given away and I would assume that it will be given away. Telegram disguises itself as encrypted chat app, when it is actually just a regular centralized plaintext messenger that has an encryption feature that nobody uses.
While Signal does require a phone number to register, they only know your phone number, your date of registration and the date of your phones last connection to signal's servers. Anyone requesting your information from them needs to provide your phone number, so any info they can get is account creation date and date of last connection.
Phone number is enough to find who is behind it in most cases.