Just installed an Atomi mini-split (from Costco) and thought I’d share my experience with integrating it into HA.
First, I installed the Tuya integration into HA, and the Tuya app on my phone. I did not use the Atomi app. After putting the mini-split into pairing mode (hold down the WiFi button for 5 seconds), the Tuya app recognized it and connected to it. Then it asked for WiFi credentials. But I kept getting an error when it tried to connect to WiFi.
A Google search turned up recommendations such as moving the router closer to the unit for the initial connection, and making sure the selected network uses 2.4Ghz. Nothing worked. But a further search result recommended using a WiFi SSID that only contains letters and numbers. For some reason, this unit is unable to connect to an SSID containing special characters. (Mine contained a hyphen. The manufacturer really should fix this.)
I set up a spare router as an access point, using an SSID minus the hyphen, and bingo! The Tuya app connected properly.
Then the device became available as a HA entity, and I was able to add a thermostat card to my HA home screen.
I did not want the unit to be running, with the fan on, during times when heating or cooling is not required. So, in my automations and scripts, I added steps to turn the unit off and on, in addition to changing the temperature set point.
Hope this helps someone!