A previous employer had the same issue, and solved it by writing the application to kubernetes and deploying minikube to the clients that didn't have their own kubernetes cluster.
To be fair, the situation ended up being: bunch of clients running minikube, 1 major client with their own kubernetes cluster, and a lot of other clients using the multi tenant, cloud hosted, offering. Made it a bit of a pain to support that one client with a cluster we could not control, but it was one of our biggest clients, so, them the breaks.
