In some countries, eBay or craigslist was never a thing. In NZ we have our local version of eBay but the success fees have gotten so ridiculously high that FB marketplace is slowly becoming the only option.
I encourage you to listen to the 4 part series Elon Musk Unmasked [1] from Tech won't save us.
His motivations are definitely not for the betterment of the average person.
I use Firefox sync between all my devices including mobiles Android and iPhone, plus EndeavourOS, popOS and MacOs.
In addition to that I use the tabs stash extension which also syncs all stashes between devices, though I only use that on the desktops/laptops