4 things

Use good screws. I only use the Morosos.

Replace the screws. Screwing into the bead dulls the point on the screws. Two uses and they are done.

Drill a small starter hole in the tire. 1/16, 3/32 maybe.

Lube the screw (JB80) and apply pressure while screwing them in.

If the results don't match the theory, change the theory.