Best tanks against higher tier opponents

I have been playing for a while but just recently started taking the games a bit more seriously. I have been trying to be more strategic in positioning and using the tanks “correctly”. I play mostly tier 5-8.

There are a few tanks that I dread going up against higher tier tanks with. Which tanks are better against +1 higher tier tanks? Or how do you play differently when grouped with a majority of +1 tier tanks?

Thank you