Limiting AMD GPU Usage with Mesa Driver

I'm running Linux Mint 20 x64 Cinnamon edition with Mesa driver. I have a game (Planet Coaster) that uses 90%-100% GPU at all times, even when the game is paused and in menus. It's a common issue and my AMD RX 580 is more than adequate to handle the game. It does this regardless of graphics settings, resolution, or frame rate cap. It's a known issue on Windows as well. Can I limit the GPU utilization in the kernel or using some other method? Trying to get around poor game/engine design.