I wouldn't be so sure about that. 2b is dinged a little in mph due to the proximity to 1b.
For example, Gabriel Arias throws 92.9 mph at SS and 85.7 mph at 2b.
If Polanco is at 79 mph at 2b and Story and Mayer are 82 and 81, I wouldn't rule out Polanco being able to have a stronger arm elsewhere. When he split time in '21, he was 78.5 at 2b and 83.9 at SS, which would be better than Story and Mayer. When Story was at 2b, he was only hitting 76 mph.