I find WhatsApp user experience lacking and I wouldn't use it if my friends and contacts weren't all there.

It's decent platform for simple sentences and trading emojis/memes I guess.

Thanks for your feedback! I agree, WhatsApp is an amazing piece of software with a great user interface & UX.

There are significant computer science challenges when building peer-to-peer software that are much easier to solve when building a centralized system. This may be the reason that people seem to "brag" when they create something p2p - because it is difficult to do - and it may also be the reason why there has not been in your opinion "a killer p2p chat app" yet.

One great thing about WebTorrent is that it makes building p2p software for the web much easier. They have done a great job!

The challenge is yours, then!

Yea, but I've no skills to make one. I am willing to pay for one, £1 per month.

Maybe because WhatsApp has billions to make sure everything works?

Even the non-p2p open source apps are less polished.

So really it has nothing to do with p2p at all.

Have you tried Matrix? https://matrix.org/

Matrix is a great project! I believe it uses a federated model which means that it relies on people donating their servers and bandwidth and messages pass through those federated servers rather than directly between peers as with WebRTC.