So what does this mean?
Solar and Wind can work but there are big demand management problems, and there doesn't appear to be any progress on allowing or requiring EVs to charge smartly (ie. based on the prevailing electricity price, including discharging).
Never gonna happen in Germany. The last nuclear power plant in Germany will shut down for good at the end of next year. Last year the share of electricity generated from renewables was 46%.
Well, Russia simply plays by the rules Europe promoted itself. You don't want stable long term "take or pay" contracts with price tied to oil and instead you want to tie contracts to spot prices? What you ask is what you get. Don't blame others when they start to game those rules in their favor when situation is right.
The debt brake can be "disable" though, this is the case right now for COVID and Peter Bofinger has made an interesting argument that one might also be able to do this for investments to defeat climate change by declaring this is a natural disaster. Although anyone who tries that probably has to make that argument to the constitutional court.
The debt brake isn't based on economic considerations though, it's rather based on ideology, much like austerity (which is known to be counter-productive when used to "save the economy"). The correct solution would be to remove the debt brake and address the problems it is meant to prevent directly, but nobody involved wants that.
Beyond that as far as I remember when reading the literature, there have been no empirical studies that found that the rate of profit was not falling, only inconclusive results or positive results.
I personally don't think it's settled yet, though. I think empirical evidence is not quite there for now.