If we had some more users (and reviewers) of different versions I could see switching to stable branches like other OpenStack projects do. Then charts could be created from say the stable/2024.1 branch and that’s only tested with 2024.1.
We can definitely discuss this during PTG. IMO stable branches exist not because it is cool and convenient but because it is impossible to do without them for core Openstack projects. In the case of Openstack-Helm it seems we can easily do all the changes backward compatible which work with all recent Openstack releases. While core Openstack projects are mostly focused on development of new features and only critical bug fixes usually require backporting, Openstack-Helm as a deployment project is always behind the cutting edge and focuses more on maintenance of existing deployments which are often two/three releases behind. Most contributions are to fix problems (that didn't appear during testing) or add new features to the existing clusters.