But dB without reference makes sense in many many occasions. Either because the reference is implicit (not ideal, but we have many implicit assumptions in communication), or because it's genuinely a ratio. Attenuation, gain.
If you every find an "official" written document that uses dB not as attenuation/gain and is not specifying the reference (at least in a footnote), it's written either by idiots or for idiots, or both.
dB(A) is a weighting. It’s not a reference and it’s not units. I think some of the confusion here comes from people not actually understanding units.
A-weighting describes how different frequencies are summed up. It’s like saying “RMS”. RMS is not units, A-weighting is not units. You can apply A weighting to voltage, digital signals, or audio. They all have different units but can all be A-weighted.
You could invent a new unit for A-weighted audio, but you would need several.
