Time for a new tonearm.
Pictured is a Technics pivot screw and locking collar. In my experience these usually have some locking compound (Loctite?) and can be very difficult to remove/adjust, you will never get it right anyway. holding the pivot screw perfectly in position while locking the collar requires, I'm sure, very precise jigs and fixtures.
The other picture shows a typical Technics bearing insert, they are similar in the damaged part of your tonearm, you can imagine that this will have been distorted with the damage to the arm, not repairable IMO. One other thought, on the arm that I used for the pictures, which had suffered similar damage, it was the lower pivot which had suffered most as it is more substantial.
I used the opportunity to fit a Rega arm.