I’ve been using a single 24 inch 1080p benq usb c monitor after realizing 4k 27 inch scaling is just terrible and 5k 27 inch is just too pricey. It’s a budget monitor but it’s surprising what 140$ can get you these days cause the quality of the panel is really good. It supports daisy chaining so I can add another monitor to my m1 air (which I can’t otherwise I think). If it was 4k 24 inch I’d buy two as I find that size kinda perfect.
Personally I’ve found that a single monitor is enough 90% of the time while coding. It’s when I need to do something nitty gritty that I need a second monitor.
That being said working with only a laptop is painful and extremely uncomfortable for the posture. I don’t think I can get anything real done without a monitor keyboard and mouse. Going down to an 11 inch iPad sounds impossible.