1U Server Rack Choice for Elixir Server

I am looking for a minimal setup for a 1U rack server to host a mobile apps back-end.

Elixir is great because I do code updates without stopping the server.

However, I am inexperienced with the type of server I should run.

Note this is a very early stage startup, so there aren’t any users yet. Likely less than 20 users.

Any suggestions greatly appreciated!

Note: I found a few here