I do kind of wonder how fast Wagner, or any other PMC really, could ramp up (and maintain something close to their 'normal' effectiveness.)  I've heard that they get some of their personnel from prison, but I have to believe that the pool of suitable candidates from that demographic would be exhausted pretty quickly.

Another random thing I never got around to mentioning is that a few weeks or a month ago or something, the CEO of Wagner is said to have been nearly killed in an attack that is said to have been the work of the British SAF.  The interesting thing about this is that I doubt that very many of the Wagner people are very nice and forgiving, and that would certainly include the CEO.  Wagner is, as best I can tell, a private for-profit business entity.  It would be quite believable that misfortune which befell Great Brittan, or more generally the interests of the crown, in the form of an attack it could be simply revenge on the part of a privateer and had nothing to do with the Kremlin proper.