hi @Anil_ci42
The german, deutch, looks like is setts, not correctly installed in Windows, or the US keyboard setting are over riding the European Keyboards.
Last ime this happened, we needed to switch the Windows 11 to US system and US keyboard now load the German keyboard into US version.
Restart PC
Set Windows 11 to German version, which should the updated latest version keyboard driver.
Go into Fortnite toggle between From German to US setting restart Fortnite.
Go into Fortnite settings and reset to German and restart Fortnite.
The only thing that may cause a problem is UEFN so try setting to US then back to German as fortnite gets its setting from UEFN, since the latest version UEFN6
My second guess is that the Quick Inventory is using hardcoded US keyboard instead of looking at the Windows keyboard map.
If you try this in the US keyboard and it works thats a job for Epic and needs some more votes from German users to vote this up.