If the developer of Rainbow Playground release a PC client, you can definitely play it on PC without using an Android emulator. However, you can have a better gaming experience if you play Rainbow Playground on PC with LDPlayer.
With LDPlayer, you can both play Rainbow Playground on your big screen monitor with better graphics, and enhance your gaming experience.
If you need to operate some accurate clicks or combos in Rainbow Playground, you can write macros to trigger combos with one key using the macro feature in keyboard mapping panel. Very creative and time-saving!