What value would regulation bring to a system that is currently working, has worked flawlessly for over 40 years and shows no need of imminent "improvement" from a law like this.

Exactly what problem would this law saw? So far all I am seeing are vaugue assurances and warm feelings but zero substance of how it would improve anything.

Indeed, if history is our guide any change is far more likely to hurt rather than help. Therefore it is incumbent on those seeking the change to defend it - how exactly will this law "improve" things. Please be specific and factual and leave feelings to the poets and philosophers.

So the argument is: medical devices yes, internet which is used for everything: no.

Not every jurisdiction in the world is based on extreme fines (like the US) but many are build on strict regulations (like most European countries).

Personally, i cannot speak about the concrete law and nis 2 thingy.

Fine then enforce that:

Any software that is used by EU citizens (downloaded from EU App Store or EU vendor website) should use EU DNS servers. (The user should be allowed to change the DNS on per device and per app lvl)

I’d be okay with that. And I think that solves your issue, my issue and EU’s issue.

Is that feasible for millions or billions of already manufactured, exiting devices?

Simply - no. Devices that are old enough which have no OS updates then... no. But any new device or already supported ones: yes why not. It's just an update from the manufacturer. You can even say: If the device is within EOL<1 year just update the DNS to the EU DNS. Other devices will need to have the option of choosing DNS addresses.

Another approach is what we do with cars: we don't ban ICE cars, we have different "tiers" (Euro5, Euro6) of emissions and phase them out. We can do the same thing. Any device manufactured after 2020 will need to implement this "feature". It will take a few years to propagate but it is a very feasible approach.

Don't most devices use just DHCP, which in turn in most cases just use the DNS settings of the Internet Provider (IP) that is being used (indirectly, as usually the local router is set like that) => if a local government asks the IPs to use specific root servers then the problem should be solved?

(or maybe I'm not understanding the core problem...)

You control the client. Don't ask my server if you don't want to. I'm not making you do it.

If you want to ask my server, send me information in the protocol that says that you want me to meet a certain standard and I'll blackhole the request if I can't meet it.

This is how SSL/TLS works and it works well.