While I love the idea of open source software and would be utterly delighted if any part of a Nothing products codebase was open sourced, it’s just not feasible. While they seem to be wanting to take a community focused approach as a company, ultimately they are commercially focused, releasing their codebase would give competitors an advantage.
While this is ok if you’re a powerhouse like Microsoft, it would just lead to copycat products that steal the idea. Can you imagine if google open sourced their software for their home hub? Within months you would have dozens of knock off smart assistant at devices. Again, while this might be ok for a large tech titan, for a upstart like Nothing it would be shooting themselves in the foot.