Mac 14' or 16' WFO

If you've haven't tried ultra-wide external monitors already, then first try that. And if you get hooked to it, then Mac display size wont matter. Then with portability in mind you can go for the smaller one (assuming processor and RAM are equivalent)

I use 16' one right now and used to have 14' one for a couple of years. I find the 14' one better because of its portability. I have realised that, the change in the screen size is not worth. I am assuming the ram and processor speed is same. If you need a bigger screen size, you can always opt for an external monitor.

I like the bigger screen but the 16' one seems a bit bulky to me and the more real-estate is wasted in the trackpad and useless sides. The keyboard is nearly the same.