"Grandiose statements" refers to statements or claims that are exaggerated or overblown, intended to make something or someone look more impressive or important than they actually are. Full definition
Instead of making grandiose statements such as, «I'm going to get rid of everything I own on Saturday,» reframe your intention into something like, «This Saturday I am committed to cleaning out my chest of drawers. (mindbodygreen.com)
Not because it's inherently funny but because there's something ludicrous about grandiose statements dripping from the mouths of anime characters in British regional accents. (independent.ie)
He makes grandiose statements which have you nodding your head, then dazzles with colourful language rather than delving into the subtlety such complex issues require. (politics.co.uk)