I took a deeper dive in Reticulum-rs. It is std. It implements 20% of Reticulum functionality. And it has 2 major protocol incompatibilities (like a different size for the MTU / Maximum Transfer Unit).
It looks like a quick vibe coded hack to implement a subset, tailored only for Beechat's own devices.
If someone would want to implement a full no_std Reticulum lib, they would need to start from scratch.
My surprise level at your finding is low. I regularly start from scratch in embedded rust for precisely this scenario. A typical response is "Why not use [reticulum-rs] etc.". Your elegant description could be described with the "But we have McDonald's at home" meme.
There are many cases where a library will be posted online, be mentioned in a blog post, and demonstrated in a demonstration workflow. If you try to use it for practical means, it becomes immediately clear it is "totaled" or easier to start over than fix or adapt it.
It looks like a quick vibe coded hack to implement a subset, tailored only for Beechat's own devices.
If someone would want to implement a full no_std Reticulum lib, they would need to start from scratch.