I only notice my pro being really good when playing Splatoon, otherwise I don't see any difference. I suppose people who enjoy other shooters like Overwatch or Fortinite may think the same, but you only listed Action-adventures and Platformers
With the joycons you can use motion controls plus play undocked; In your position I would never buy the pro before the joycons, if your joycons are fine then you can buy pro