Mine are doing great thank you, after using Randy Oliver’s oxalic acid sponge method for Varroa control. 
It isn’t totally legal yet everywhere, but it is totally safe. The US EPA is working with him on getting it properly approved - shouldn’t be too long now. So your choice, but if you are willing to try it, you may be able to cross Varroa off your list of culprits:
We have one weak hive with a queen that has never laid well, but they made it through the winter and are building up now. We will probably boost her with a package and a queen replacement. Such is the role of a livestock manager - keep monitoring and do what you have to do for low performance…