Using a large bracket in PAGES

Any selected text will vanish with the next key press. Is this what you have in mind? I dropped an SVG left brace into Pages and added it to My Shapes. I selected the paragraph and indented it .5 inches. Then, I inserted the shape and cleaned up the alignment. I have been meaning to replace that brace shape with something less bold…

A simpler method is to insert a new Text box and while selected, visit the Arrange panel and set Text Wrap to None. Insert your favorite font character for the brace symbol in that Text box, select the brace, and then use the font size increment tool to enlarge the brace to fit your paragraph size. Then move into place, like so where I am using a custom Cormorant Garamond Light font at 119 pt.