how to remove a stubern nut / lower control arm

You use a Channel Lock plyer, or bigger vice grip on the back end of the shaft, going up between the lower control arm, and the crossmember, clamping down on it, keeping it from twisting.
Easy, peasy.

Then a 15/16 six point socket on the end of a 1/2 inch breaker bar, or big 1/2 drive ratchet, and then go at it.
Or, one of these will zap it off very quickly.

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