Dropship on eBay. Which seller address should I use?

I'm a total noob when it comes to dropship, and I recently tried to make a listing on eBay. I'm buying from Amazon and sell on eBay. But I live outside of US and I already sold an item.
Now, my question is what to put in the seller address?

On eBay in the "Ship from" section it says "You need to have USA address. Click "Change" to create new address or select an already added USA address." Should I put my supplier from Amazon address there or what do I do?

I am also started this but still now no sales. what i do is. once i got order i enter the buyer address.

I would go for a usa drop address...

Which site would you recommend for using a drop address?

I have one problem while listed items on amazon.

My dropship company can deliver items in 1-3 (max time they need they said) but why Amazon shows my delivery time of 12-19 days? Who goanna buy my product if I take 12 to 19 days just to deliver the product? How to deal with that? (My dropship company is based on Georgia, US and my profile show I am shipping from Manitoba, Canada)