What is the minimal docker base image to run a unity based server?

Hello together,

i currently run my gameserver instances in docker containers with I base on the official Ubuntu18.04 image. Question now is: Is there a better way to do this with Unity? Are there perhaps dedicated images which run a minimal system that is needed to run Unity?
I so far was not able to determine an answer to this as most docker related discussions online only relate to using this for build instances.

The only thing that i currently have to add to the Ubuntu image is a curl installation to support webrequests. Everything else is already included but i feel like there must be a more lightweight solution to this out there.

Any leads in this regard are greatly appreciated. (Let me know if this is the wrong place for this discussion, i was not sure where to go with this)