Docker with Image as OS?

We have a dedicated server who’s only purpose is to run a Docker image (a web server for internal work). It feels like a lot of extra work to maintain a let’s say Ubuntu server, keeping it update etc when the only thing it should do is to run a Docker image.

Is there any way I can build a Docker image on my dev machine, turn it into a bootable iso and then just boot our server with this - having it all in the RAM memory? If so - how does the deployment procedure work?

I know there are services for this, but we need a big amount of cores, that’s why we do this on a dedicated machine.

Thanks