Debating between Home Assistant OS or Docker for Raspberry Pi 4

You can go supervised! You still have most of the operating system available to your needs and you can still use add-ons. I use it for years and it works like a charm

Running it on a bare Pi, HAOS, imho you get the most performance, and support if it goes wrong.

Running on more powerful hardware (x64 host), VM all the way. It's so much easier when you can snapshot, move VMs around, and split out components when needed.

I run my own a VM.

I was sceptical about running in a OS that I can't run my normal updates and automations on but HA OS has been rock solid and easy. Plus you get a few more features

I have HA running in docker on a Pi 3 and Z-wave JS running in another on the same Pi. Added a purpleair integration for outdoor air quality, national weather service, some local sensors, and sql to get data from another node. People have made me paranoid about SD card failures, so I regularly image it to my main server. I mostly use HA to visualize environmental data, but it also runs the lights in a hydroponic farm and the house during vacations, via z-wave outlets. Have not tried to integrate it with google or amazon.

The only inconveniences I've found with docker is that you can't restart HA from its web interface and, if you update regularly, old images quickly fill a smaller card, so you have to remember to purge.