Shopify has a solution to the second bullet, at least here in the US. Shop Pay provides a common set of login, payment and package tracking services for stores

Shopify has a solution to the second bullet, at least here in the US. Shop Pay provides a common set of login, payment and package tracking services for stores on the Shopify platform. This is great for small stores that don't want to implement Apple or Google Pay. I have been buying direct from the manufacturer or from small shops since I cancelled my Prime subscription in 2023 [0]. Many of them use Shopify with Shop Pay enabled. It's great. The only negative about it (which I knew going in) was that next-day shipping is (rightfully) much more expensive, if they offer it at all. As far as postage goes, you're out of luck there. Amazon runs their own logistics and shipping network. They can afford to offer next day delivery at deep discounts no-one else can match. [0] I cancelled it but apparently still have it, and going to the Prime management page throws an error.