> I think there is a real hole in the market for a simple solution that lets you deploy some containers to some instances in a declarative fashion without all of that complexity and does decent LTS versions. I imagine there’s something out there that does this, but k8s has really sucked up all the oxygen.

I mean, it's CDK and whatever equivalents other providers have, isn't it? If you fully embrace all the stuff they give you then it's straightforward to declare everything and it all works together. The downside is the vendor lock-in but unless you actively deploy to multiple environments, which most people don't, you're probably locked in in various ways without knowing about it.