Interesting questions! At this time, there is no way to bulk-import products. Unfortunately, you will need to do it one-by-one from Aliexpress or the Oberlo marketplace. It was designed this way so that merchants would really focus on the individual products they would be selling in their store. However, I can see the benefits of bulk-uploading if you already know what you want. I will definitely pass this suggestion on to the product team!
In regards to shipping times, I would suggest checking out some of the suppliers in the Oberlo marketplace that have warehouses in Europe. There are only a few so far, but we are adding more regularly. They will likely offer faster shipping times to Germany.
If those suppliers don't have the products you'd like to sell, consider selling elsewhere first! I'm in Canada but only sell to countries that have better shipping and conversions. Over time the shipping to every country will decrease, and when it does for my home country, I will consider opening up selling here as well! This way you will be able to start your business and have it ready to go when shipping to your location becomes more accessible.