Research on honey bee colonies that are naturally resistant to varroa (ie: no beekeeper intervention) is more instructive to learn from IMHO. The traits of these bees against varroa are the same in different parts of the UK, Europe, sub saharan Africa and South & Central America. It’s hygienic behaviour that’s repurposed for varroa. The bee’s traits to look for are illustrated at:
www.varroaresistant.uk
There are scientific papers published there, curated by Prof Stephen Martin, together with case studies from UK beekeepers of how they got there. I hope you find it helpful as a resource.