> EU alternative to Google, Microsoft, Apple, Twitter, Facebook, Amazon

This is basically just saying "we need to start by replacing 5 of the richest and most powerful companies the world has ever seen".

I think the EU should start a little smaller so they might actually make some progress on digital sovereignty within the next century.

You don't have to do all five at once, and a proper replacement based on the integration of a number of partial solutions should in principle be workable. What is required is the capital and the will to do it. If someone pulls this off they can count on my company as a subscriber and I think there are many more like me.