the fear is not about Windows but the online cloud service Microsoft365 and yes to offer an European alternative to that service you need shit ton of money to operate a datacenter big enough to offer services without lag or data size problem for millions of users (at least if you want to be a real concurrent to Microsoft365).
on a smaller size, there is Nextcloud in the Open Source space that integrate a lot of tools that Microsoft365 has... So a good start exist for a more privacy solution, but that's on you Brussel to create full time jobs to makes open source MR/PR to improve the scalability and the feature of Nextcloud while staying true to the open source spirit...
As a GNU/Linux and BSD user I can't be agree more.
For the funding, Brussel as the money... If they decide to reroute the money they spend to GAFAM to their Open Source equivalent projects instead Nextcloud, Mastodon, Peertube, Matrix, etc... would not stay under-fund.
The sad thing is that there was an official Mastodon and Peertube instance that stayed up for years but was highly under-fund itself. The European Commission decided to cut the few funding left in 2024, closing both instance.