If I consume all the clean energy your country can produce with my data center, explain how cap and trade blocks a country from using other sources - I don’t think anyone will like news stories of people freezing to death in the winter.
Of course, would the latter happen, political actions would be done before people freeze. It will be unpredictable what the would be - allow fossil fuels "temporarily" or order datacenters to shut down during dunkelflaute? Interesting times (I would prefer less interesting times).
Generally speaking cap and trade is the most sure way to reduce emissions (emissions drop exactly at the pace the CAP drop annually) and the most cost-effective way also - the TRADE part ensures emissions are cut first by those who it easiest, while hard-to-decarbonize sectors have most time to sort their plan.
The only problem is "carbon leakage" where co2 emissions simply move to asshole countries like USA and China that do not utilize cap-and-trade. That should be dealt with hefty carbon tariffs. Oh wait, even china is building their own cap-and-trade system. Well, anyways, tariffs against the climate assholes.
For example, gas heating is exempt from the EU carbon trade, so people are encouraged to use that rather than electric heating. In countries like Germany, gas heating is popular largely for tax reasons.
carbon leakage is mostly industrial and data centers (why do so many europeans run code at us-east-1 ?)
The EU has a carbon tax on electricity but not gas. This pushes people towards gas heating. Germany has much higher taxes on electricity, although it does at least have a carbon tax on gas.
If a carbon tax on electricity makes people use gas heating, that's carbon leakage.