Let's not forget that it was the US that didn't want much nuclear capability in Europe so they offered to protect us with their nuclear umbrella. They strongly objected to Italy's nuclear program for example.
Now that the US umbrella can't be relied upon, we will need our own. I do think it's the main reason Europe has been safe since WWII.
Unless we live on another planet Russia can barely fight a war against Ukraine and their military capabilities have been further eroded for decades with insane losses to their personnel, economy and equipment.
There is one, and only one country in the world in the position to threaten Europe in any way, and it's our most important ally.
*Ukraine with very significant support from various countries
Russia on the other hand is shit at waging their war in Ukraine but they achieved their objectives (land bridge to Sevastopol, etc.).
So the worry is not that Russia will wage a well fought war, but some war at all, even if they are shit at it, because it will do extensive damage either way. And we know for a fact that they don't shy away from it.