There are many resellers, and some official shops.
Also, this is China you're dealing with. It's a known fact that authenticity to them is not a strong suit - everyone claims to be "official" and "authentic" all the time when shopping there, especially those selling fakes.

Just exercise your own discretion and make a judgment call for what's best for you. Sometimes cheapest is not the best, and sometimes it's cheap enough for you to ignore the fact that it's obviously not official. User comments help, but feedback can be faked (sellers can just buy their own products to leave fake reviews). Caveat emptor applies while shopping online.
There's a reason why people are willing to risk online shopping - it's already cheaper than retail because they don't bear the additional middleman overheads of rental, utilities, staff, and of course reseller profits... You could always pay two-four times the price by traveling to a mall and buying it there if you wish. The same is true even across the various platforms - resellers have their own pricing, but are still cheaper than brick and mortar retail anyway. You choose where you want to buy from.
Don't expect them to set a standard retail price across the board - they are not dealing with high profit margin items like mobile phones and laptops.
Challenger's house brand cables are also sourced from the same Chinese suppliers. If you observe carefully, some local brands appear very similar to Chinese OEMs that are probably rebranded by resellers. For example, there's a Titan Power cable I saw in Popular for as high as $34.90, and on Shopee we see the exact same OEM by McDodo that goes as low as $1.79 - same description, same shape, same green LED light, same nylon braiding, same L angle connector. Whichever you choose, it's your money so you decide. For me, I have a few of the McDodo cables and find them decent.
https://titanpowerplus.com/pages/titancable
To put it in perspective, just a few years ago, the "good" cables were all in the $20-40 range with the brands like Anker, Imation, Sony etc. Today they're around $2-10 and the quality is as good as or even better than "good" cables in the past thanks to the named brands like Ugreen, Vention, Baseus, USAMS, McDodo, etc.
tl;dr: Not happy with one shop (cos too expensive, cos not official, cos <insert your own complaint>), buy elsewhere that makes you happier. But once you buy it, just accept it as purchased and move on. No point comparing and saying "I should have bought from <alternative platform> cos cheaper/better/faster/buy1get10000free/etc."