Can't confirm that it's only 15W, but my Thinkpad T14 Gen3 AMD is charging, but the battery level is slowly dropping with active use.

Correct, for me it is completely sufficient. No comment on the assumption.

Ah no sorry wrong product, I was talking about my Eizo 27" sorry

No idea how much W but I can charge my Lenovo t14 with it without any problems

Answered the question yourself. Research has confirmed exactly that. The USB-C port can only be used for video/data transfer, not for charging a laptop or MacBook.