This is no add-on, it is direct inside HassOS. Also you can restore a snapshot direct at HassOS onboarding after a fresh installation.
Yes, I have. I have Add-ons like AppDaemon 4, Hgonx Proxy Manager, TasmoAdmin etc., Integrations like Homekit, Logitech Squeezebox, MQTT, HACS, Phoscon etc. and I have things installed via HACS like ControllerX, Argon40 etc. And all are restored fine.
Before I had a Pi 4 with HassOS 32bit 4.x on a Boot-SD card and SSD for data and now I have a Pi 4 with HassOS 64bit 5.7 and SSD only.