Hello fellas 
A few days ago my girlfriend (the best girl ever!) gifted me a RGB Ducky Shine 5. I absolutely LOVE it. I was always looking at them telling that this is the best board that I can imagine to get some day and now i am writing down this with it

I have one question for the once of you that are familiar with it. Is there any way in the world to make the backlighting mode like rainbow? Like when you press FN+Space to select a color. I watched videos tried everything myself but there seems to be no such mode or easy way implemented.... This seems kind of absurd to me so I thought that maybe the problem is with me and decided to ask you guys in here.
I don't have the same k-board as you and I don't know if I understand you right but on my Ducky One RGB YOTG k-board I have this:
FN+F10
First Mode: Color Cycling Mode
Second Mode: Wave Mode
Third Mode: Snake Marquee Mode
Fourth Mode: Raindrop Mode
Fifth Mode: Reactive Mode
Sixth Mode: Ripple Mode
Seventh Mode: Aurora Mode
Eighth Mode: Backlighting off
To get the Raindrop Mode I have to press FN+F10 4 times.
The manuals for Duckys t-boards are not so good to read, they could make the manuals a bit more easy to read.
Edit: This is for single Color LED:
FN+F9
First Mode: 100% Full Backlight Mode
Second Mode: Breathinng Mode
Third Mode: Wave Mode
Fourth Mode: Snake Marquee Mode
Fifth Mode: Reactive Mode
Sixth Mode: Ripple Mode
Seventh Mode: Aurora Mode
Eighth Mode: Backlighting off
My white Ducky One RGB YOTG.

My Ducky One RGB with Jukebox SA keycaps set and my ISO/Nordic Ducky Shine 3. The 2 orange Pumpkins don't belong to the Jukebox set.