It seems like it's still possible to disable Gatekeeper on macOS 15: https://discussions.apple.com/thread/255759797
I haven't tried it though. It's so rare that I want to run something unsigned, I prefer leaving it enabled and then allowing whatever it is I want to run.
Not for much longer unfortunately. He will likely be elected the next chancellor when early elections happen sometime in the next months. It's also not unlikely that he will willingly form a coalition with the far-right extremist AfD that love to suck on Putin's tit and have supported the idea of Ukraine ceding territory to Russia.
He's a disgusting piece of shit and this is just him using Ukraine to fish for votes.