You got a point, though I am not sure which things you are referring to. For example https://en.wikipedia.org/wiki/Stasi tried to have tight control in east Berlin but eventually failed. China is doing currently the full scale automated information gathering and control against Uighur Muslims. Not sure how China is using propaganda for the Chinese themselves. Also NSA uses mass surveillance already at the moment for foreigners and internal political opponents.

But propaganda as a weapon is not a thing to underestimate. As investigated e.g. Jessika Aro https://www.igpub.com/putins-trolls/ and some might argue about the role of election interference for the Trump election and re-election as well.

Even highly educated people are susceptible to propaganda eventhough they consider not https://www.mpg.de/24132917/0205-bild-online-misinformation-...

So, if the leaders are dictators and hates people, it wont be good with or without new surveillance laws as there are already existing ways to do that.