I was thinking physical mail too. But I think It definitely would require some sort of system that is either third party or government backed that annonomyses you like how the covid Bluetooth tracing system worked (stupidly called track and trace in the UK). Plus you’d have to interact with someone at a postal office to legitimise it. But I’m talking, just a worker at a counter.
So you’d get a one time unique annonomysed postal address. You go to a post office and hand your letter over to someone. You, and perhaps they, will not know the address, but the system will. Maybe a process which re-envelopes the letter down the line into a letter with the real address on.
This way, you’ve kept the server owner private and you’ve had to involve some form of person to person interaction meaning, not a bot!
This system could be used for all sorts of verification other than for socal media so may have enough incentive for governments/3rd partys to set up to use beyond that.
Could it be abused though and if how are there solutions to mitigate them?
OK, it’s possible it’s a template Google made available for android developers. I find the YT music app easy* to navigate so quite like it.