The Danish data protection authority (Datatilsynet) has issued an injunction regarding student data being funneled to Google through the use of Chromebooks and Google Workspace services in the country's schools.
Nextcloud is a very solid cloud solution which doesn't suffer from those data leaks. https://nextcloud.com/
You do not have to sell the chromebooks, you can replace the OS with fedora. You can customize your OS acording to your needs with ublue https://universal-blue.org/
I applaud your optimism that there are enough people employed in the school IT to do that properly.
Don't get me wrong, you are absolutely right with those statements, but the schools used Chromebooks for a reason I would think, the same reason that if they had not used Chromebooks it would be some Windows installation.
It is what people know, it is "easy" to work with and so on. Those are obviously not great reasons and not 100% true, but that is what counts for those schools.
I am very curious what they are going to replace this with and I am unfortunately 100% sure it is going to be Windows and the Onedrive/Outlook ecosystem.
Thats great and commendable. But the fact is the schools do not have that running, else they would not need the Chromebooks in the first place, would they? They still have to get this started which means employing and paying someone to do this, having budget for paying the servers and whatnot. Seeing how efficient governmental work is, it won't be as easy as borrowing some server capacity from a different government agency plus one of their IT guys for a short while.
Concerning the cloud workspace, it would be possible, that the IT services of the Danish regions (or of the whole state) run centralised clouds (Nextcloud, Moodle, ...).
In our university we have an Ansible playbook to set up firewall rules etc. and change the network share and user logins so that they can't access the Internet or any previously saved files.
Depends, it's definitely something you can automate so it works at the click of a button on some website (and another to revert). We just run the commands from the terminal.