Hi munjal
1. Why don't use use LPC-Link2 J7 as debug interface? Please try J7 debug interface instead.
2. refer attached video, if Jlink commander can detect LPC Core?
3. If 2 fails, Please use LPCScypt update LPC-Link2 firmware, try both CMSIS-DAP and Jlink interface respectively, to make sure LPC-Link2 onboard firmware no issue.
4. If 2 detects LPC core successfully, try to use MCUXpresso IDE to test the connect, MCUXpresso IDE can detect debug interface automatically without other setting.
5. Is your LPC54608 board custom designed PCB? If yes, refer this article to check the interface design
https://community.nxp.com/t5/LPCXpresso-IDE-FAQs/Design-Considerations-for-Debug/m-p/469565#M44
Thanks,
Jun Zhang