I just downloaded Fedora 41 KDE. When I tried to install it, I discovered that I couldn’t change my keyboard layout in the live CD environment, either in the KDE system settings or in the installer. After installation, the system’s keyboard layout was set to what I chose during installation, and I could also switch to other layouts in the system settings. However, it was inconvenient; without my familiar layout, I could only set my password to “abc” and then change it after installation.
The problem is not only the user password, but even more so if you want to set up full disk encryption! This bug makes this release/installer image unusable for non en/us-keyboard users, which means the majority of the world! And beforehand, setting a temporary bullsh** passphrase and change it later is not an acceptable workaround when we talk about encrypting and securing a system!
I can confirm, i use an AZERTY keyboard layout, and none of the settings seems to work to change the keyboard layout on the live image, thankfully you can just set up your password to a temporary one, and then the changes are taken into account after the installation, however this would be quite problematic if you want to setup full disk encryption, i’m not experienced in reporting bugs to Fedora so other than responding to this topic i’m not sure how this can be properly brought up, feels like as alternative layout users we’re second class citizens 
One workaround I discovered is to use Fcitx5. After installing it, go to the virtual keyboard settings and select Fcitx5. Then, add the keyboard layout you want to use. The trick here is to keep the US keyboard as the default layout and add your preferred layout as an additional one. When you need to use the other layout, simply switch to it, but don’t delete the default layout.