macOS Big Sur low fps

Running Minecraft was fine until I recently updated to macOS Big Sur... Now half the time my FPS is at a normal 60-70 FPS which is perfect, the other half it's at 30 FPS and lags like crazy... I am pretty sure this is a fault on Apple's part but Mojang may need to update something for macOS users as well to solve this issue... Something to be concerned about...