Regardless of configuration settings, RGBTW lights report 0-600 as the range to Homekit. It appears these values are hardcoded. Although you can set color temperatures using the color picker all the way from Tuya’s min to Max - the Mired values shown by Homekit are miles off. For example, I have Feit color bulbs that go from 134-370 Mired. Whether I configure them to this range or use the default 140-400, Homekit Controller shows the min/max Mired as 0-600 (Homekit certified bulbs like Hue, Meross, Nanoleaf show their actual range) - and it appears the actual converted range is from 71-600. So if I use either the Tuya app or the Home app, setting to warmest color correctly sends white:1 to the bulb - but Homekit shows the bulb is at 600 mired rather than the actual 370. If I set all the way cool, the bulb receives a white:1000, which is 134 Mired, but Homekit shows 71 - the converted minimum value.
Regardless of configuration settings, RGBTW lights report 0-600 as the range to Homekit. It appears these values are hardcoded. Although you can set color temperatures using the color picker all the way from Tuya’s min to Max - the Mired values shown by Homekit are miles off. For example, I have Feit color bulbs that go from 134-370 Mired. Whether I configure them to this range or use the default 140-400, Homekit Controller shows the min/max Mired as 0-600 (Homekit certified bulbs like Hue, Meross, Nanoleaf show their actual range) - and it appears the actual converted range is from 71-600. So if I use either the Tuya app or the Home app, setting to warmest color correctly sends white:1 to the bulb - but Homekit shows the bulb is at 600 mired rather than the actual 370. If I set all the way cool, the bulb receives a white:1000, which is 134 Mired, but Homekit shows 71 - the converted minimum value.