>Lets say the primary force we need to prevent is russian influence campaigns that back and push far right nationalists who will destabilize democracy. Is that a sufficient reason for controls?

No. Because if you solve underlying tensions in society the so called russian propaganda has nothing to take hold on.

Also who and under what rules will decide which propaganda is allowed? is American propaganda fine? Chinese? Japanese? UAE?

Not only this creates dissident, and suppresses voices critical of current government. but also gives extraordinary power on level of soviet union to current government.

You might trust current EU to not abuse it, but it might take a single elections, or single term for un-elected(!) officials in EC for attidute to change.

Just like in US - a lot of powers were granted but suddenly there's a person willing to abuse them.

For that to be even considered in EU we would need a lot more check and balances - especially for European Comission and Council.

Another issue is - is EU a trade union or federation? if former - this is outside of EU's responsiblities and powers. if later - look at point above.

If you really wanted to solve this problem you would go after advertisers and data collection companies, and regulate them.