For ~$1M you can successfully attack and completely compromise essentially any Fortune 500 company in the world.
For ~$1M you could target the current model year of any brand of car in the world and develop a remote attack to simultaneously target every car of that model year at rush-hour and engage the cruise control at maximum speed, engage the anti-lock braking to disable the brakes, and, if applicable, engage the autosteer to turn slightly into oncoming traffic as these researchers [1] demonstrated could be done 5 years ago on a budget of only $80k.
For ~$1M-10M you could likely target the most popular types of generators used in a power grid and at the very least deactivate if not disable their software governors and over-rev them to destroy them as demonstrated by the DoD 14 years ago [2] and as militarily deployed by Russia against Ukraine [3] which could result in the loss of power for months if sufficiently widespread.
At the very least our internet-connected stoves with remote turn-on [4] are safe since, as we all know, the software developers for stoves are the best minds of our generation so it would cost far more than the ~$1M to hack a Fortune 500 company to remotely turn on the gas at 2 AM in the morning and then the igniter at 3 AM with results like this: WARNING [5][6].
For less than the price of a tank any government can develop a weapons system that is comparable in power to a full scale nuclear first strike that you can deploy instantly in your enemy's territory. Not just that it can be tuned to any scale of destruction you want from an individual all the way up to full scale nuclear strike, and it can be done untraceably or, even better, you can pin it on one of your other enemies as the CIA had the capability to do [7]. Frankly, any government not feverishly developing such weapons systems given that they only cost a few measly million to develop for the immense capabilities they provide is either ignorant or fighting the last war. This is The Tool that a small nation can use to achieve parity with superpowers given their miniscule cost and immense leverage.
[1] https://www.wired.com/2016/08/jeep-hackers-return-high-speed...
[2] https://www.youtube.com/watch?v=7GSEchbDuB8
[3] https://en.wikipedia.org/wiki/December_2015_Ukraine_power_gr...
[4] https://www.geappliances.com/ge/connected-appliances/ranges-...
[5] https://www.youtube.com/watch?v=a2JPLMzQjkk