Helm globally controlling values of dependencies from requirements

Question

We have a set of Micro-Services (MS-a, MS-b, MS-c..) each has its own dependencies specified in requirements.yaml. Some have the same requirements, e.g mongodb.

For deployment of the overall application we created an umbrella-chart that references all MSs as its dependencies in requirements.yaml.

We provide a single values.yaml file to the umbrella-chart. That contains all the values for all the MS charts. That works fine till it comes to providing values to all the dependency charts of MS charts. One prominent example would be mongodb.clusterDomain

In values.yaml file the clusterDomain value would have to be repeated for each MS section:

MS-a:
  mongodb:
    clusterDomain: cluster.local    
MS-b:
  mongodb:
    clusterDomain: cluster.local

that screams for trouble, when it comes to maintainability. Is there a way to move those values to some global section, so that it is only specified once ? e.g:

global:
  mongodb:
    clusterDomain: cluster.local

I have tried to use anchors https://helm.sh/docs/chart_template_guide/yaml_techniques/#yaml-anchors

it would look like that:

global:
  mongodb:
    clusterDomain: &clusterDomain cluster.local
    
MS-a:
  mongodb:
    clusterDomain: *clusterDomain   
MS-b:
  mongodb:
    clusterDomain: *clusterDomain

It does not reduce the structure complexity, but it makes it easier to maintain, because the value needs to be set in one place only.

however, it seems to have a very nasty pitfall when it comes to overriding values via --set. According to the link above:

While there are a few cases where anchors are useful, there is one aspect of them that can cause subtle bugs: The first time the YAML is consumed, the reference is expanded and then discarded.

It practically means it will not be possible to override the clusterDomain values by providing:

--set  global.mongodb.clusterDomain=cluster.local

because it will only replace the global section, while all the other places will remain with their original value.

Is there any other way(s) to make it possible to set subcharts values globally in one place?