Just because you are at sea level, you can't suddenly float stuff in the air. I like your optimism though. :) I was imaging a floating city like cloud city in star wars [0].
This is a bit more thought out than perhaps OP applied, several theretical investigations have been done into floating cities on venus and it more or less comes down to building blimps out of gasses like nitrogen and oxygen. Because the venus atmosphere is so dense, this would actually work.
[0] https://www.starwars.com/databank/cloud-city