I’ve tried to explain this, also linked to the relevant documentation, but I’ll state it again: Homey’s Thread support only pertains to Matter. And Matter is something that’s beyond the control of applications, it’s entirely handled by Homey itself.
That’s not what I said, I said that I don’t think Athom will add HomeKit over Thread. But I’m just a community member, I don’t know the actual plans that Athom has.