Hello @justus_bunsi, thanks a lot for taking the time to participate in the community.
We are actively working on changing that release model as we know it is really confusing.
Let me first introduce the short future, what will be the new model, and then i’ll try my best to explain the current one.
Starting from the next helm release, we will consider helm-chart-sonarqube really intertwined with the SonarQube product. That means will have a one to one mapping of the version.
If SonarQube is at 10.X the chart will be at 10.X also (we will have the same for the docker images).
And starting from the Next LTS release cycle, the LTS chart will also follow this principle.
Now lets jump on the actual model 
What we have right now is a separate lifecycle for the helm chart, which is really not linked to any SonarQube version.
The main rule is that when a new SonarQube version is released, we bump the major version of the chart.
apart from that, we add feature and bugfixes whenever we want in master, bumping chart major minor or patch depending on the type of fix.
Furthermore, if we have new versions on master, we release on the artifacthub only when a new SQ version is released (or in case a major critical bug / security issue is to be fixed)
This is why in artifacthub we see that the last released version are :
But if you look at the changelog README or the github release your were pointing, you will see the intermediate version.
## [8.0.0]
* Update SonarQube to 9.9.0
* Bootstrap chart version 8.x.x dedicated to SonarQube 9.9 LTS
## [7.0.2]
* Update the list of supported kubernetes versions
## [7.0.1]
* Set a new default (maximum) allowed size of the client request body on the ingress
Small notes on the github release vs artifacthub.
Github release is were the zip is stored, and the artifacthub is just linking to them ( done with that summary file
On top of all of that, before, we had a separate chart with a separate folder and code base for the sonarqube-lts. now the sonarqube-lts is a dedicated version of the chart
I hope the new one will be much more user friendly.
TLDR: current release model is considering the helm chart as a separate product.