Lenovo Ideapad gaming 3, can't adjust screen brightness with Ubuntu 20.04 or 21.04

This question is similar to quite a few others here, and I've tried a few things without luck. A brand new Lenovo Ideapad works like a charm with Ubuntu 20.04 (later updated to 21.04), except that the screen brightness cannot be adjusted in any way. Not by the slider control found top/right on the screen, not the Fn+F5/F6 buttons (only the graphic indicating brightness change is showing), nothing.

sudo lshw -C display:

  *-display
       description: VGA compatible controller
       product: TU117M [GeForce GTX 1650 Ti Mobile]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
       configuration: driver=nvidia latency=0
       resources: iomemory:fc0-fbf iomemory:fc0-fbf irq:79 memory:d0000000-d0ffffff memory:fcc0000000-fccfffffff memory:fcd0000000-fcd1ffffff ioport:4000(size=128) memory:d1080000-d10fffff
  *-display UNCLAIMED
       description: VGA compatible controller
       product: Renoir
       vendor: Advanced Micro Devices, Inc. [AMD/ATI]
       physical id: 0
       bus info: pci@0000:05:00.0
       version: c7
       width: 64 bits
       clock: 33MHz
       capabilities: pm pciexpress msi msix vga_controller bus_master cap_list
       configuration: latency=0
       resources: iomemory:fc0-fbf iomemory:fc0-fbf memory:fce0000000-fcefffffff memory:fcf0000000-fcf01fffff ioport:1000(size=256) memory:d1500000-d157ffff

lspci | grep -i vga:

01:00.0 VGA compatible controller: NVIDIA Corporation TU117M [GeForce GTX 1650 Ti Mobile] (rev a1)
05:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Renoir (rev c7)

Any idea what I can do to help this?

BTW: the machine does not have any Windows system on it at all. I run Ubuntu exclusively, normally very happy with that.

The issue is the nvidia proprietary driver. I was facing the same issue with every single Linux distro i installed. You can either create a fresh installation (make sure to not select "install proprietary drivers") or you could just uninstall the proprietary drivers and switch back to the nouveau driver. You can see how to do this here: https://linuxconfig.org/how-to-uninstall-the-nvidia-drivers-on-ubuntu-20-04-focal-fossa-linux