Diablo IV hangs on class selection and forces a reboot

Hello my friends,
I bought Diablo IV (From The Steam Store) And Installed It On My Steam Deck OLED.
Once I Link My Battle.Net Account And It Gets Through The Prologue And Reaches The Class Selection Screen Everything Is Ok, Until I Change Anything In The Graphics Settings Menu And Then It Stutters And Hangs On Class Selection And Shortly After It Forces A System Reboot.
I Need Your Help With Instructions To Fix My Issue As I Have Been Dealing With This Issue For About A Week Now.
If Anyone Had This Problem And Has Successfully Nipped It In The Bud, Please Share With Me The Fix.
Cheers All,
Oliver.