Not much new in that article. You could do this about 10 years ago.
You can actually do most dyndns with an http GET. Just a ping. Though GET is not supposed to have side effects, it works well.
Proper relays on phone will be really good.
In this discussion Nostr could fit well:
https://news.ycombinator.com/item?id=35944315
nostr:npub1melv683fw6n2mvhl5h6dhqd8mqfv3wmxnz4qph83ua4dk4006ezsrt5c24 I'm thinking about https://github.com/nostrapps/fonstr too.
Discussion
I know it is not new and technically feasable by a lot of time, all the tools are already available; but could be a really nice concept to push the Nostr decentralized nature and support the Gossip/Outbox model to the extreme: read my content on my self-hosted relay. Of course we need a great UX, installing the relay should be as easy as a client; or perhaps the client could offer a build in relay (and use it as storage?) + a dyndns service.