I have a native install on a Debian LXC - 16GB storage, 2GB RAM and 1 core, that I’ve been running for over 2 years behind nginx. Doesn’t need much. If you want to record via Jibri, you need more juice. I will be redoing my install as they now offer an all in one Docker stack with recording capabilities. With the native install it is recommended to have a separate Ubuntu 18.04 server for Jibri just for recording, which is a hassle and outdated.
I haven’t begun the Docker setup yet, but I imagine it has to be a more pleasant experience to admin.