Heyho 🙂
the URL of the services archive that does not change title or content when changing in the customizer is:
https://progress.computermate.de/service/
The testimonial archive is at
https://progress.computermate.de/testimonial/
I will try to tranlate the plugin via Poedit to resolve the issue temporarily, but I guess (or hope) it’s not just my fault, since the customizer options simply have no effect at this point. I already translated my theme to resolve some other language issues.
For concretization: the issue was present before translating anything.