I don't get it, you praise the IPhone's ability (and ease of use) because it can record continuously at 240fps. On the galaxy you can choose between the "super slow motion" that you tested and regular "slow motion" where it has the exact same characteristics as the iPhone 240fps slow Mo.
In case you weren't aware regular "Slow Mo" is disabled by default, you have to go into camera settings, down to Edit camera modes enter into the"rear camera" section and then turn on "slow motion".
I have an S9+ and loved the idea of the super slo mo feature but unless I am outside during the day or in extremely well lit indoors it films too dark to really see anything. Quite the disappointment really