This tutorial is aimed at improving finger strength & dexterity.

https://www.guitartricks.com/tutorial/1829/

This one does the same, but targets the pinky.

https://www.guitartricks.com/tutorial/1292/

Having said that, in some cases it's okay to use your ring finger.  Using one finger per fret is a good default setting.  But sometimes the musical context requires a different fingering. Especially when doing pentatonic scales like you mention, because you might want your ring finger available to do a bend.

For example:

https://www.guitartricks.com/tutorial/1614/

https://www.guitartricks.com/lesson/13754

Hope that helps!