A plurality of meanings is not necessarily a plurality of self-subsisting beings. Knowledge, power, and life can be differentiated conceptually while predicated of the one essence.
Classical objections invoke numerical ranks and the relation of part to whole, showing why numerical or conceptual distinctions need not match independent external substances.
Ignoring this difference produces two mistaken alternatives: either every divine attribute loses its distinct meaning, or every attribute becomes an independent necessary being. The careful account rejects both inferences.