Thank you for sending over the schematic. For the feedback pulses waveform, it looks like noises coming from the SW node or gate. It shouldn't be the root cause of regulator not able to achieve 30V/4A.
The Ccomp value on C6 seems to be larger than usual, it may cause stability issue. The recommended value would be 47nF for C6 and 1~3kohm for R10. For this 120W design, please pay attention to the thermal performance. Shorten the FB trace as much as possible and avoid running the traces near the SW node. In addition, if you are working on the EV3910 evaluation board, the board is designed to output 2.5A at 24V. You might run into some thermal challenge in 120W 30V/4A design.