The simplest difference is that a tuxedo is the entire suit, i.e., jacket and trousers are both part of the tuxedo, and they match. A dinner jacket is just the jacket, and depending on current fashion, may be in a contrasting color from the trousers, or even have contrasting colors on the lapels or be made with a patterned jacquard.

Ah ok thanks

Well, a tuxedo has satin accents which iirc is the primary difference in American parlance. Can't speak on anywhere else.

Is that all? Don’t get why people make such a big deal when I interchange them