A consistent look across every slide, set once instead of per slide, is what themes are for.
Design tab — a theme sets fonts, colors, and layout style for the entire presentation in one click.
Design tab → Design Ideas suggests layout variations for the content already on a slide — worth trying before manually rearranging anything by hand.
View tab → Slide Master opens one master slide that controls the look of every slide using a given layout — edit the master once (font, logo position, accent color) and the change appears everywhere that layout is used, instead of editing every slide individually.