I have been using this docker image and setup to create the container, which works.

this docker image is not maintained anymore, meanwhile the image build fails so the image is old without containing security fixes. Also this image does not contain the latest mm version v2.16.0.

I deployed a service running the Magic Mirror image from that on port 8075.

can you show us this service? kubectl get service <service-name> -o yaml

I wrote a helm chart for running mm in k8s, you find it here.