Hi Lindsay.
I’m on a Pi 4 with Home Assistant OS (Raspberry Pi - Home Assistant).
Re containerisation: With Hassbian being plain linux, it was straight forward to locate files / paths / where and how to install things. With haOS, SSH is via an add-on that allows access to that add-ons container, and “This add-on will not enable you to install packages or do anything as root” (from it’s docs).