‘Of the statues, those by Lysippus – whom Alexander thought was the only one worthy of depicting him – best display the appearance of his body. For those things which many of the Successors and Friends later copied, i.e. the straining of his neck, gently inclined to the left, and the pliancy of his gaze, this artist has accurately observed.Apelles, in painting Alexander wielding the thunderbolt, did not copy his skin-colour, and made it insufficiently pale and a bit too dark. Alexander was pale, as they say, and the paleness turned a bit red, especially on his chest and also his face. Also, his skin smelled very sweet, and a fragrance was on his mouth and his whole body, so that his clothes were filled with it – I read this in Aristoxenus’ Memoirs.’

This description of Alexander comes from Plutarch’s Life of Alexander (4.1-2), and seems plausible enough, even if very broad. But despite the fact that in your question you are most suspicious of his sweet scent, this is in fact the only detail here that Plutarch cites a source for, and it’s a pretty reliable source as well: Aristoxenus was a fellow student of Aristotle, so both a contemporary and likely to have met Alexander himself. That isn’t to say that he didn’t embellish or invent this detail, but I’m not sure I see any reason to completely reject this information. As for Plutarch’s other details: concerning Alexander’s alleged paleness we get only the classic ‘they say’ (who say?), and this may be a detail intended to suggest Alexander’s always latent erotic potential; for the statues Plutarch's reasoning seems off, since the sculptor who makes the statues that you like best is not necessarily the sculptor who makes the statues that most accurately reflect your real appearance.

But statues are certainly the best place to start if we want to consider Alexander’s appearance, or at least the parts of his appearance he most wanted to depict. We cannot tell, due to the paint fading, what colour his skin or hair were on the statues, but this is unlikely to have really been important and I think is at any rate unlikely to have been particularly true to life. Alexander’s statue-type is very distinct and formed the model (as Plutarch says) for most of the successor kings, which means we have hundreds of copies, across different media, of Alexander’s key features. Somewhat generic aspects are his musculature and his youthfulness, though this latter is important to note: at no stage does Alexander appear to have depicted himself as a mature adult, perhaps to contrast his iconography with that of his father; see e.g. https://www.britishmuseum.org/collection/object/G_1872-0515-1 (Alexander) vs. https://en.wikipedia.org/wiki/Philip_II_of_Macedon#/media/File:Philip_II_of_Macedon_Ny_Carlsberg_Glyptotek_IN2263.jpg (Philip II). Eternal youthfulness becomes a prominent literary theme in the Hellenistic Period, particularly in compositions at the royal courts, which is suggestive of the influence of this motif.

Two features of the Alexander statue-type, however, are highly unusual. First of these, and most prominent, is his hair: it is medium-length, slightly curly, and very loosely arranged – it always seems permanently on the verge of falling over his face. Contrast this with e.g. https://en.wikipedia.org/wiki/Motya_Charioteer#/media/File:StatuenMozia.jpg (the Motya Charioteer) or https://en.wikipedia.org/wiki/Harmodius_and_Aristogeiton_(sculpture)#/media/File:Tiranicidas_04.JPG (in particular Harmodius, the younger man on the right). Perhaps this hair evoked certain divine connotations, but it is not an exact fit there either. The other notable feature is the diadema, a thin band of cloth wrapped around his head, a little above the fringe. This item was the definitive feature of Alexandrian kingship, and possession of the diadem was essential for all later kings. Various theories have been thrown around as to what exactly the diadem was – a Macedonian crown? A Persian tradition? Egyptian maybe? But none of these have particularly convincing evidence behind them, and there are no precise parallels nor helpful attestations from ancient authors. Instead, I think the solution is likely to be the simplest one: it was a hairband worn by Alexander, and worn so frequently that it became emblematic of his rule, and eventually synecdochic for Hellenistic kingship overall. So to return to the original question: much about Alexander’s appearance cannot be known for certain, and depends on the testimony of later writers; given how historically significant Alexander, skin-colour, and hair-colour have been in nationalistic and racist discourse, I am wary about engaging in any speculation at all. What I think we can know relatively (and I stress relatively) for certain is that he had curly, medium-length hair, and managed to make hair-bands really, really cool for centuries.