@taylormccue I use 2160p these days, but 1080p is much more common as far as I know and scales neatly to it. 🙂
Are we talking pixel art? Scaling that between 1080p and 720p can basically not be done well as I understand it, but the "golden path" would be to have all the important bits inside a 720p canvas and then extend the margins with content (or a decorative border, see Undertale console ports) to 1080p. Integer multiples of those two resolutions should then cover most current displays.