This is how I see things.
Amm is a race, not a breed. Like all races it contains terrific genetic diversity. Some genes and alleles are shared by all honeybees (the species) a very small proportion are rearranged and observed as different subspecies, or races. Occasionally a mutation, or loss of genetic material will create a unique characteristic within a subspecies.
The vast proportion of what creates a different bee, a subspecies, race, breed or local variant, is multi-generational environmental conditioning. As that happens, each unique environment goes to work on the available material to produce a population that is unique. In Northern Europe the product is known as the variety of Amm.
That's the first part.
Now look at how all this variety (within ie Amm) is connected by geographic proximity. Genes and gene-packages (alleles) are constantly being swapped with neighbours - but not (in the natural state) with more distant ones.
So variations change gradually over distance. Geographic obstructions, high mountain ranges and sea separation allow relatively close populations to become marked different. But otherwise we are largely talking about gradual change with distance in all directions, with each 'local population' being shaped by it's local environment; and, importantly, most genetic material held by all populations - just merely unused, unless needed.
This is the picture we need to have in mind when we talk about hybrids, and about local 'survivor' populations. Such populations are being constantly conditioned by their environments, and the process of natural selection for the fittest strains is diminishing the presence in them of less-useful (here, now) genes and gene-packages, and increasing the presence of genes-that-work-well here.
They are being shaped into bees that belong here. And early reports are that those packages contain critical Amm features.
So, left alone (no imports, minimal clumsy beekeeping) Amm is returning. Partly as a spread of the injection of surviving Amm genes from Amm-rich populations, partly from such genes that never went away; all being appropriately sorted and winnowed by natural selection.
This is all minutae that you don't need to know (and I suspect you don't understand as well as you think you do).
Think of it like this:
You know you need to keep putting petrol in your car if you want it to keep going. You don't need to know all the tiny ins and outs of why that works.
Stop importing, stop treating: local Amm populations will return. That an option. That's all you need to know.