There should be an option to enable the dedicated GPU only for Dolphin, and this should be on. If you have done this, and it doesn't work, then there should be an option in your bios to completely disable the Intel HD 3000, but not definitely, as it can run your battery down ridiculously quickly, so may have been left out the laptop bios.
OS: Windows 10 64 bit Professional
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56