If someone wants to understand 5G PHY layer in depth:
5G Wireless Standard Design complete course, university-level, but explained in a calm and simple way (as much as possible, given that some concepts are truly complex).
Watch Videos on YouTube: https://youtube.com/playlist?list=PLFW6lRTa1g81SMpel8aIFBubvO0h1UOJV&si=wkk0ePMFAU4uolW_
1500 minutes! (60 videos)