Question: do you guys care why people are selling things? I've been doing transactions on Kijiji and elsewhere for 10 years, and I've never asked why someone is selling something. I just go with the obvious: they don't need it anymore, or they need the cash more.
I also sold an iPhone XS Max with AppleCare+ until October 2020. Context clues should make the reason for the sale obvious: it was clearly bought not too long after it launched and is being sold a year later; clearly I'm selling it to upgrade. Yet I had this dude meet up with me at the Apple Store and grill me about the reason for the sale before purchasing, despite being provided with the receipts and all warranty info.