Yes? It isn’t complicated. Both are correct, but I would add that the word dungarees is effectively non-existent in American English, maybe 1 in 100 people would know what you are talking about off you used that word here. And coveralls are the only word we would use to describe what you call overalls. And the only word we use for what you call dungarees is overalls.

It’s almost like there are different versions of the English language, and search engines are designed to give you results that favor your region/version.

I can’t speak to the inflatable part, but people in fat suits that weigh little, they still look fat.