Bigger Custom Breakpoint as default

My preferred layout sizes are 1440px or 1980px. I then set this as the container width in the settings. Do I then have to set 1440 or 1980px as the default breakpoint at the beginning? I have the effect that desktop default values ​​are not adopted at 1440px or 1980px. They have no effect (font etc.)

Do I have to pay attention to anything before starting work?

Thanks for answers.
Jens