Athom will say that it’s an issue with Kwikset because they need to certify their devices, but it’s happened before that devices that were certified were still rejected by Homey as being uncertified (looking here, the Halo Select seems to be certified recently, but Homey should download certification information periodically to keep its database up-to-date).
Also, Homey is about the only Matter controller that strictly rejects devices that aren’t certified.
