Germany's stance on nuclear is dumb, no doubt, but my understanding is that most German homes/businesses don't heat their domiciles with electric heat, but rather with natural gas or heating oil. So it's unclear to me that more nuclear development would be an answer here.
Probably the best answer, honestly, would be to look to other sellers to help bridge that gap. I've read that discussions have been had to import gas from other sellers, and it could be an area where our own domestic supply could help as well (we are now a net exporter as well!)... but in terms of making Germany (or others) whole, that's gonna be near impossible, but it will force them to adapt and diversify their energy portfolio, which could make them less reliant and hurt Russia in the long run.