I believe you are correct that it only works with Gen 2+ ATOMs and I don’t think I even have an Atom 1 around anymore. I use an Atom 2 to run my landscape lighting (8 dimmable zones) and it has worked pretty well. Also, for Atoms, make sure you override the wss:// encryption to something less compute-intensive than ECC because my benchmarking showed a huge difference in performance on the Atom2 when using ECC vs. SHA-256. See my in-line comments here ezlo-hub-kit/src/EzloHub.ts at efd3ae843421564c24e96e00a35889ad27cad1b4 · bblacey/ezlo-hub-kit · GitHub
That said, ezlo-hub-kit was my attempt to create an off-device SDK that we didn’t have, and ideally, could codify the lore in a single place for the use of many others… In fact, you may recall, I refactored the kit from my in-work HomeKit bridge when you announced MSR thinking that it might be of use for integrating Ezlo Hubs into MSR.
Finally, sorry for the slow reply but I can only post from my desktop because my forum email can’t be confirmed for some unknown reason.