Today I’m using version v4.12.4 (because a bug was fixed that made it impossible to edit the component form) .
And in another project, the v4.11.2 .
In both I use the same code and they work
Your controller/service file inside is “…api/myCollection/services/myCollection.js” or “…api/my-collection/services/my-collection.js” ? Strapi requires filenames in kebab case to work
If the code is not something private (company etc) and you want to share part of your code / repository so I can see how the calls are organized, feel free!