I know that the card is not good, but I think it is not normal that the laptop does not use a percentage of it, as you can see appears with a 0% while I'm running a game.
If I could help I would appreciate it very much.
There are lots of HP Pavillion G4 models so you would need to provide the full details of your system when posting an issue. Also the AMD System monitor is rather out of date and shouldn't be used as a performance metric.
The Hewlett Packard website should document how you switch between both GPUs depending on if you want power saving or a bit more performance. So start with that first. Could be in the motherboard BIOS for example.