Basically, if you want to build an on-premise offering, look at the way Nginx, Postgres, Redis and similar projects are packaged and do the same.
Nope. You should look at how an app that uses all of those is published. That’s what on-premise software truly is. A combination of dependencies and your companies secret sauce.
Your own app code is just one cog in that engine.
These are orthogonal. Resourcing is no guarantee of ops competency, or a culture where ops is enabled to deliver, hence the concept of shadow IT. On-prem software is bought by orgs with low risk appetite or other compliance objectives that skew procurement towards running on prem. I have seen exceptional ops teams on a shoestring ramen budget, and I have seen dumpster fire ops teams in companies with thousands of workers and billions of dollars a year in revenue who could not get you a single virtual machine in less than 90 days even if preventing the end of the world depended on it.