If Europe does't buy gas from Russia then that leaves Qatar and the US. Qatar does sell a lot to Europe (hence you'll notice how "friendly" Europe is towards Qatar) but is vulnerable to instability in the straight of Ormuz.

The US are making a fortune on gas at the expense of Europe an it's not that the promise to buy gas is meaningless because unenforceable within Europe, it's that it was already happening in practice. And that makes Europe even more dependent on the US (while the complaint was that we could't buy gas from Russia and depend on them).

There is plenty of gas in the EU; we decided that it was undesirable to extract. Honestly pathetic; strategic autonomy and energy security is much more important.

Russia killing hundreds of EU citizens should be enough to stop buying gas from them.

Yes, the EU does rely on buying US gas as an important part of its energy mix. But that is true independent of whatever deal the EU struck with Trump. The EU simply does not have control of who its gas importers buy from (other than sanctions)

But this is also why the EU is aggressively pursuing and building up alternatives, including investments in Canada's ability to export LNG, but also buildouts of solar, wind, and batteries.

Solar and batteries come with their own dependencies on China, but at least those are a different sort of dependency than fossil fuels. If China stops exporting solar / batteries, the ones we have will still keep functioning for decades while alternatives are built up.