Use a TRIAC to connect/disconnect a capacitor to a PSC motor
I suspect that snubberless means that the traic does not need dv/dt snubber but still may need di/dt protection. Switching capacitors will result in high di/dt. That is probably the mode of failure. You will need to add di/dt protection to the circuit or use a relay. A higher current triac might work without di/dt protection.