Everything flexbox can do, CSS Grid can do, with easier/better/cleaner support for the second axis. At this point, I'd be interested in dropping flexbox entirely for CSS Grid.
("I don't need to worry about the second axis" seems to be a "not thinking fourth dimensionally enough" excuse to me today. You haven't considered enough responsive breakpoints or you haven't considered future features or future expanded data or future localizations, yet.)
Everything flexbox can do, CSS Grid can do, with easier/better/cleaner support for the second axis. At this point, I'd be interested in dropping flexbox entirely for CSS Grid.
("I don't need to worry about the second axis" seems to be a "not thinking fourth dimensionally enough" excuse to me today. You haven't considered enough responsive breakpoints or you haven't considered future features or future expanded data or future localizations, yet.)