I tried Carniolian bees once which were supposed to be more docile. After a year of getting stung up I killed the queen and replaced her with one I cultivated pre swarm from another hive I had had for years.
Varoa Mites are terrible. I used to keep a bee yard with twenty or so hives all in a cluster. Now I scatter them about 100 yards apart so the mites don't hitch rides.
The only hive loss I was seeing these past couple years were keepers that did not leave enough honey behind during these bitterly cold winters up here in the north east. I have two hives going strong and caught a swarm about two months ago that from the looks of things I either got the queen or they produced a new one. Either way, it’s been six plus weeks and I have new brood and almost ready for a super.