02 sensor removal help

so im working on my GF's parents nissan mini truck with a 2.4L... and im trying to get the O2 sensor out... well like everything else on the truck they never have replaced ANYTHING... plugs had no strap left on them lol...

any ways i tried the o2 socket but no dice... its a 22mm but it wont grab enough of the last to sides due to the cut out so it just expands and spins...

im been sprayin it with PB all day and tapping it with a hammer to try to loosen it up (not hitting the sensor)...

getting ready to weld something to it and go that route...

bummer is that it has a complete crack thru the manifold between the front and rear banks so i really would rather just get a hole manifold... grrr....

any advice?