Which is almost literally a tale as old as time. This sequence:
invade another country to take their shit
oops it's not going so well
hire mercenaries with no morals to wreck stuff
don't pay your mercenary bills and/or attack them for being too powerful
the mercenaries sack your own cities
That's not just modern times, and it's not even just medieval times: I'm pretty sure at least one Assyrian king was deposed that way. People like Putin are doomed to repeat history, it's their lot in life.