I feel like investing in p2p approaches and having people donate spare server capacity might be better. For example, relay calling was p2p in the original Skype and worked well. Apple private relay is a similar concept whereby there are two intermediaries to make things private. It gets trickier since in mobile land you can’t run servers really, but I feel like the Signal population has enough spare capacity to offload bandwidth and stuff and could be an easier sell than “please give us money”.

For the sms verification, I feel like forcing the requester to do some bitcoin mining for you could potentially pay for itself.