Pages - A "dark mode" kludge
If you're accustomed to working in Dark Mode, using Pages as-is can be a blinding experience (that huge white background). After poking through the options, I've found this to change the background color:: At the far right in the header, select "Document". In the panel that opens, choose "Section", and behold! a "Background" control appears. With nothing selected in the document, choose your desired background color. Then select a chunk of text. In the header select "Format", which gives you a "Text" panel, then choose "Style." The panel that opens should give you options for styling your text, whatever color works for you. (If you select the entire document, you may not see the Text Color" tool there, though.) I'm using Monterey 12.6.2 on a MacBookPro with M1 silicon.
I hope I haven't skipped over a vital step anywhere, and hope this makes sense.
iMac 21.5″