There is an action for unpairing and repairin homekit. devices Although, for me at least, it was not very straight forward to use, because the homekit devices are not shown in the UI in the selection dropdown menu.
You can, however, enter the device ID manually in the YAML Mode in Developer Tools > Actions:
action: homekit.unpair
target:
device_id: DEVICE_ID
I did not find the device id of the homekit bridges at first, but if you go to the integration an click on the Service the bridge provides, you can copy the device id from the url.
Note that all the custom names and areas you use inside the iOS HomeApp will be lost after this process.