I agree sovereignty is important, but that also means that EU residents will be subject to the whims of EU politicians. And increasingly they have been pro censorship, pro surveillance, and anti actual democracy (for example intervening in elections). The concept of democratic sovereignty mentioned in here should include freedom of speech and free elections, but at present having tech sovereignty would risk those things further.
Over 74% of all publicly listed European companies depend on US-based tech services, like Google and Microsoft.