That's an interesting suggestion; thank you!
Font size will definitely be an option regardless of which layout we end up picking. Having "standard" and "compact" layout options to pick from is something to consider.
Discussion
Yes, the font option is critical for usability and accessibility. Since it is sometimes not so easy to manage it dynamically, mixing it with a couple of static density options is a good move to provide effective options without crowding preferences and complicating development.
Otherwise, the classic approach is to have 3 fonts, 3 spacing options and let the user combine them.