There's an even easier way in Protools, and ideally there would be the same in Studio One: Right click on a track name then select "Spit into Mono"
There can be 2 alternatives which should take very little time for S1 devs to implement, test and release:
A. Add the "Split to Mono Files" feature to files in the pool. This way, we could Right-clic the stereo event/ Audio / Select in Pool then use the feature.
B. Add event Right-click / Audio / Select in Files. Hence, we could use the "Split to Mono Files" with ease.