Signal is not good for normies: compare sending a message with Signal to WhatsApp. Didn’t go through? WhatsApp will try try try to resend. Signal tries far less then shows the dreaded red exclamation point. Not great while travelling or with poor reception.
Signal developer here: we should retry with reasonable backoff for 24 hours before showing a delivery failure. If that's not your experience, please file a bug if you get the time!
Thank you for all you do. All of my grandparents joined Signal to message me and they have no issues for the most part. Although, one of them didn't know to press the download icon on photos I sent. I'm not sure why they weren't downloaded automatically.
Also please accept cryptocurrency for buying username-based accounts. The overlap between people that want to buy an account and those that want to use a fully identified payment method is not a lot.
I spend about half of every year traveling the mountains and deserts of the world, often ones with poor infrastructure. I use Signal more than any other messenger app, and I have never had the deliverability issues you complain about; messages do all get through eventually.