Spindle spinning can be very efficient. Think about it as a knitting machine compared to two pointy sticks. While staying at the machine, it knits more per time spent. but the machine needs dedicated space and time. You can't walk to the mailbox while using a knitting machine. But two pointy sticks can happen anywhere.
When I compare wheel spinning to spindle spinning, I can get equal amounts done in a day.
If I'm doing single ply sock yarn on a low whorl spindle, I can spin enough for a sock in under two hours.
There are some really good books on how to improve spindle efficiency.
Respect the Spindle.
(and another one I'll try to find)
I sadly don't know enough about website creation to know how to create a sales website. We do have a digital market here on permies, which you can sell physical items on. It is a bit harder to sell physical items on the digital marker than digital items (there's no easy way to add in shipping prices for different countries. You can see an example of a physical item sold on permies through the digial market here: https://permies.com/t/fairy-grove-chicken).
But, you can totally make a thread on permies with your stuff. You could even post prices next to items and direct people to PM you, or post paypal links for purchasing. We've got lots of options here!