Dell precision 5470 shutdown and suspend issues on Ubuntu 22.04

Hi,

The Dell precision 5470 came pre-installed with Ubuntu 20.04 but I need Ubuntu 22.04 so I overwrote the old system with the latest ubuntu version.

The laptop is working well but I'm facing two issues :

- on shutdown, the laptop does not shutdown on its own; I have to press the power button for some seconds to switch it off completly

- I close the LID or trigger a suspend, the session never recovers. The screen remains black and there is no other solution than pressing the power button to do a hard shutdown.

Does anyone know how to fix this or at least to dig into the problem for trying to find a fix ?

Thanks for your help,

Best;