Remove Orphaned Entries is the right answer here.
Removing the integration will create problems if you have renamed the entity names of devices. You would have to do all of those over again. And with deconz integration there is a feature to remove them. Unfortunately HA itself does not care much for removing devices and does not provide the developers of integrations a common UI to delete devices. And I repeat Devices! You can remove entities if and only if they are not owned by a device. But there is no feature to remove devices. Each integration has to invent their own ways to delete devices. Some still cannot do it at all. Others do their best like deconz. But it is well hidden. You may also sometimes have to restart HA after you run the removal service. I have seen that