Bug Report

Description

Right after the installation I could not change the layout. Although I did get the notification about successfully changed layout and no errors were popping up.

Output of SwitchKeyboardLayout.sh script

$ ~/.config/hypr/scripts/SwitchKeyboardLayout.sh
Starting script...
Current layout: ru
Reading keyboard layout settings from /home/barsky/.config/hypr/UserConfigs/UserSettings.conf...
Available layouts:  us ru
Number of layouts: 2
Current layout index: 1
Next layout:  us
Switching layout for asus-wireless-radio-control to  us...
invalid arg 2
...
Switching layout for at-translated-set-2-keyboard to  us...
invalid arg 2
Switched the layout for at-translated-set-2-keyboard.
Layout change notification sent.

Explanation

As you can see in the output there are no critical errors, but there is some issue and that is invalid arg 2. After a brief exploring in Hyprland Docs I discovered this:

hyprctl switchxkblayout [DEVICE] [CMD]

where CMD is either next for next, prev for previous, or ID for a specific one (in the above case, us: 0, pl: 1, de: 2). You can find the DEVICE using hyprctl devices command.

DEVICE can also be current or all, self-explanatory. Current is the main keyboard from devices.

But in the script there is this:
hyprctl switchxkblayout "$name" "$new_layout"

where $new_layout is symbols, like us, en, ru, etc.

Solution

Just change hyprctl switchxkblayout "$name" "$new_layout" (64 line) to hyprctl switchxkblayout "$name" next or use layout index instead of 'next'.
Im not sure that I didnt somehow messed up the installation or post-installation stage, but that`s what I got out of the box and how I fixed it.