The study reported on in the link below looked at self-reported comfort levels with various airline seat dimensions. This study finds that going from 17" to 18" seat width was perceived as adding roughly the same amount of comfort as adding 4" of pitch.
I guess my own buying patterns support this, as I avoid coach in 10-across 777's and 9-across 787's.
How about you? If you could only choose one, would you be more comfortable with more width or more legroom?
https://runwaygirlnetwork.com/2021/08/19/optimum-aircraft-seat-dimensions/