The Pride Racing Newton SX crankset compression bolt — M20x1 aluminum, 15mm under head, 5mm Allen interface, 4 Nm maximum torque. The preload bolt that compresses the crank arms onto the spindle during installation. If yours is stripped, you overtightened it. Replace it and use a torque wrench: 4 Nm is the spec, 4 Nm maximum.
Thread: M20 x 1 | Length: 15mm | Interface: 5mm Allen | Max torque: 4 Nm | Weight: 10g | Fitment: Pride Newton SX only