Lack of enough wind and sun is basically what happened in EU end of last year and caused energy and gas prices to sky rocket. It is not as rare as you think, moreover it happens over large areas at the same time which exacerbates stress on the grid.
this is true
> Russia closing part of its huge gas supply to Europe
this isn't, afaik. Russia doesn't sell on spot market, they prefer long term futures contracts, on which they reliably deliver. They delivered on their 2021 commitments a bit earlier, hence they closed off the valves
Basically, the gas supplies were low during summer, but the spot prices were significantly above long term average, so energy companies delayed their purchases, hoping the price will come back down soon. It didn't, reserves dried up, and everybody was forced to buy at the same time