I was hesitant to document things like that.
Services such as signal have a reason (even if we don’t agree with it) why these services are adamant about phone number verification. There is only a limited amount of services that provide workarounds. By making these workaround more and more popular, the more likely it is felt as an issue from services who are adamant about phone number verification. It pushes them to find ways to blacklist the whole service if that is possible somehow or to use things such as google SafetyNet which can either not be circumvented, no known circumvention methods known to the public or require insecure practices such as rooting the phone with software from dubious origin and so forth.
It’s similar to private Tor bridges. The more people know the IP of a private Tor bridge, the more likely it gets leaked to a censor and added to the blacklist.
If not scalable, robust some things are better kept as hidden gems. Such as, users finding these services by digging deep, reading forums, OK but otherwise I don’t recommend to open the floodgates.