Second monitor not working

Hello, I am using Linux Mint 19.3 Cinnamon (5.4.0-42-generic) with the following Graphic devices:

Device-1: Intel vendor: Lenovo driver: i915 v: kernel bus ID: 00:02.0 chip ID: 8086:3e9b
Device-2: NVIDIA vendor: Lenovo driver: nvidia v: 450.57 bus ID: 01:00.0 chip ID: 10de:1fb9 Display: x11 server: X.Org 1.20.8 driver: nvidia resolution: 2560x1080~60Hz OpenGL: renderer: Quadro T1000/PCIe/SSE2 v: 4.6.0 NVIDIA 450.57 direct render: Yes
00:02.0 VGA compatible controller [0300]: Intel Corporation Device [8086:3e9b]
	Subsystem: Lenovo Device [17aa:22a8]
	Kernel driver in use: i915
	Kernel modules: i915
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation Device [10de:1fb9] (rev a1)
	Subsystem: Lenovo Device [17aa:22a8]
	Kernel driver in use: nvidia
	Kernel modules: nvidiafb, nouveau, nvidia_drm, nvidia

After updating the OS on NVIDIA Settings Prime profiles:

  • if I select NVIDIA GPU only the external monitor (HDMI) works
  • if I select Intel GPU only the laptop monitor works

what can I do in order to solve this issue?