it looks like the radical should be 154 貝, which “近” is the phonetic component.

This character means "near", so 近 is actually semantic and phonetic. The text in the evidence describes this as an E1 structure. This is what Prof. Hồng calls "đẳng lập hội ý" (等立會意). In this case, the character is compounded of 近 for its primary meaning and, by assimilation, the radical of 賒 "xa", which means "far". The assimilation reflects the fact that the 2 characters often appear together in the word "gần xa" (near and far, here and there, etc.). 154 貝 would be appropriate as a second radical, but based on the semantic, the primary radical should remain 162 辵