Ecommerce software for Amazon, Ebay and Shop

Hello my ladies and gentlemen,

I am currently planning to start an e-commerce business in the US and it is quite difficult to find suitable software for my needs.
First of all, I'm from Germany and have been working in e-commerce since 2010, so I've always used German software for my work.

Now I am looking for a software that is able to:

– Sync my eBay and Amazon orders with one click and sync tracking numbers after shipping orders

– Add my new products to both platforms

– simply print out my shipping labels

– Automatically send e-mails to customers after I have sent the orders

– Dealing with returns with the software

– Be able to be connected (also required) to suitable accounting software so that I can send the required information to my accountant without much effort

– It must be able to supply me sales statistics etc.

– Preferably, it is software that is properly installed on my computer. However, the database can be hosted online so I can access it from any computer

– preferably not a system running in a browser, I've had pretty bad experiences with that

– Also important is a system that also offers a webshop, which is connected to the database, so that I can easily retrieve the orders from the shop

– The store software should have SEO tools and some marketing tools, such as: Google Shopping, Adwords, etc.

– There must also be a system for VAT issues, which is very important

I have worked with JTL here in Germany, a great system, but in the US it does not work properly due to the distance between my computer and the servers.

I hope you guys can help.