This bridge is quite difficult to destroy completely, but of course even if it is damaged or destroyed, Russia will rebuild it again, but it will be much more expensive and difficult for Germany, France and the UK to rebuild relations with Russia, and they will have to do it anyway.

I wouldn't worry so much about the channel. Russian politicians are more concerned about the welfare of the West than their own country. They will make sure nothing bad happens in the UK and France. Maybe they will launch a nuclear strike on some miserable Ukrainian village or Russian city as another warning.