I have seen this "repair" video in the past, but let me makes some points.
I don't recommend an impact driver even with a proper clutch.
I also do not recommend a torsion wrench pry bars.
Automotive tools should not be used on pinball machines.
This is not a car tire!
Most of these tools unless you know the tension settings are not set up for this purpose.
If the either wrench is used with too high tension, it can damage the playfield, both underside and topside.
You have no control to see what is going on top of the playfield with the magnet core, when you do this either if the core is peened.
Factory installation is different as the tools are set at lower power settings.
Both these options are "hillybilly deluxe" amateur methods, and completely overkill to some of these potential issues.
Fortunately, he did not use a pneumatic impact wrench which is even worse, as these have nearly no control and are extremely powerful.
The video clearly mentioned he was "trying to get it done quickly" which was accomplished.
He also had no "ball shield" on Sparky to prevent jumps on the playfield in the first place, which greatly reduces issues from the gameplay perspective.
REMOVE the magnet assembly from the playfield completely by disconnecting the molex connector and playfield screws, and use an adjustable wrench, by using the first nut as the locking point which is already welded.
You can do this with two hands, and two wrenches, and should not need a any type of "vice" as you should not be holding on the magnet coil wiring anyway.
If the magnet assembly cannot be removed due to core peening, lightly tap with wooden dowel and rubber mallet to loosen it, but keep the screws in place, but slightly loosened. It will come out, and if you are careful, it will not damage the topside of the playfield with chipping.
After replacing the core, and proper leveling, use locktite for securing the position of the core before tightening.
It will not get loose.
Not everything on the internet is the "best method".
Protect your games.