Micro-services application on premise without Kubernetes?

I are migrating a big application from multi-server monolith to micro-services, this software is not a SaaS but on-premise.

The current architecture leverage a database for each server, and many requests need to be processed by multiple nodes to create one cohesive answer, so far this architecture was fast,low-resources, but really painful and time-consuming to maintain and most important without HA.

Installations scales from hundreds of servers to a simple single server setup. Asking every customer to setup a kubernetes it's not feasible, only a limited subset of customers have the skills to deploy and maintain it.

I've been searching for a simpler way for customers to deploy and maintain the infrastructure for months, seems like everyone jumped from on-premise to SaaS leaving a hole in-between.