Body odour is a social construct

Took them well over 200 years to invent it, and the other item known as antiperspirant was invented for surgeons to not have slippery hands, not for aid with body odor.
That's now something you know that you may not have known.
Deodorant baths existed in the 16th century, I believe. Body oils and flowers were used in bath water to help keep the body smelling fresh.

People thought the smell was a problem and came up with perfumes and layers and special washes to deal with it. At first deodorant, as we know it, was a failure. Marketing made it happen.
Same with toothpaste. Yes, people cleaned their teeth, but not with toothpaste. The list goes on at great length.
I know people hate to think they are influenced by marketing, but we are.

A little bit of this and a little bit of that. Hygiene and odor are issues humans have cared about in various ways for as far back as we have reliable historical records of any body of substance. It goes beyond unpleasantness- though that is certainly part. At the most basic level hygiene is a survival imperative. If you stink for a prolonged period, that stench is in part a sign of microorganisms growing on you. If we don’t mitigate their spread- we tend to develop or spread sickness. Unpleasant odors tend to be unpleasant because of evolution- we are averse to smells that signal “danger.” Smells can also be a sign of danger- sickness, disease, or rot. Humans have various mechanisms of response to this- one proposed reason why many people throw up when they see others throw up or under various stimuli is that the body is responding as if it may be poisoned for example.

What “smells good” or “bad” is to a degree cultural- some things are fairly universal across most of a species- humans like salt, sweet, various tastes or smells that signal caloric density or necessary elements- but to what degree and in what combination can vary. The same is true of scent, and scent has strong ties to memory, so we do tend to gravitate towards scents which are familiar and perceived positively. We don’t have a lot of records from faaar ancient history on hygiene practices- writing may not have existed or be hard to come by, and hygiene isn’t always something that makes the history books. Things like scented products tend to be consumable and often don’t leave a record we can trace from long decomposed remains the way certain foods or technologies can leave traces in bone etc- but we do have some evidence of various scented products from burials and such going back thousands of years.

We can say with reasonable certainty from records that many ancient civilizations had concepts like perfumes or incense, infused waters and oils etc. thousands of years ago Egyptians used scented fats kept on person, often in the hair, that melted in the heat and would produce fragrance. We also know that through history hygiene and scent have often been marks of class or wealth. The same that for a long time in much of the world tanned skin was seen as “lower class” amongst similar genetic groups because that implied one needed to be outdoors and did labor, for much of recorded history where manual labor and sustenance farming were the norm of “lower classes,” it would be difficult for them to maintain a “fresh” scent and appearance with their lifestyle requirements and resources available.

So asides the evolutionary proclivity to seek comfort, or the avoid stench; asides the survival based reasons hygiene and smell have long been important, there are various social factors at play too. To sum it all up- while we can’t say for certain through 40,000+ years of human history- we can say that at least in the past several thousand years, scent has been important to humans as it pertains to our bodies and body odors. There are various cultural differences- there is an oft memed piece of historical evidence where an occupant of modern Western Europe opines that the Vikings bath and comb their hair and those actions give the invading makes favorable status in the eyes of females of the time. So we can’t view the issue through only the lens of one culture. We can probably assume that at the very least it wouldn’t have been long after our ancestors started creating proto “civilizations” that someone somewhere started to try and smell nice.