Hitler didn’t really purge (the military) until they tried to kill him. I am no fan of Hitler—but I think his purge made sense in his mind. Stalin, he was just paranoid.
There was that ‘Night of the Long Knives’ thing from 1934, under the guise of “nipping treason in the bud”. Not that such action would EVER be considered by our current regime, but I bet they’d love to be able to get away with it...