I think Australia is mostly set up this way. We call it "One Vote, One Value". Each member of parliament is meant to represent roughly the same number of vote

I think Australia is mostly set up this way. We call it "One Vote, One Value". Each member of parliament is meant to represent roughly the same number of voters, within a +/- 10% tolerance. When populations change, voting boundaries are redrawn. https://en.wikipedia.org/wiki/One_vote,_one_value https://en.wikipedia.org/wiki/One_vote,_one_value