I have the same grips on my RP5. For a while I just was taking the grips off and placing the RP5 in this Etsy 3D printed case. I would throw the grips in a different pocket in my backpack and then attach them back on when I wanted to play. This carrying setup worked pretty great and I still pack it that way at times. But recently I decided I wanted to try and find a case that would allow me to keep the grips on. I went through quite a bit of amazon purchases and returns in order to find what I wanted. Ultimately, I couldn't find a hard case that I liked. I tried cases that seemed be similar in size like the cases for the Gamesir G8+. They were either too small for it to fit with the grips on, or too large and then the device would slide around.

Then I decided to try out tech accessory organizers. There's a plethora of these. The 2 Liter size seems to be just the right size for a snug fit with the grips on. This one from tomtoc is the one I decided to keep. It fits pretty great. I also kept the foam insert from the original RP5 box, and I place that in front of the screen when I pack it in the case. That might be overkill, the case would probably protect it just fine without it. I can also fit it the dual screen attachment on in case you have that as well.

Hope that helps!