SUMMARY
Using SDDM-wayland at F38 (and F37 too), when trying to export plasma configurations to SDDM (theme, colors, etc) it doesn't export mouse cursor size, and apparently when no cursor size is specified SDDM-wayland is defaulting to size 36 which can look a bit odd (big) on some monitors.
When we open and manualy edit the file in /etc/sddm.conf.d/kde_settings.conf, adding the line CursorSize=24 (or whatever you wanna use), then it works fine (its a workaround, I know).

Reproducible: Always

Steps to Reproduce:
1.open plasma-systemsettings and set a specific cursor size (lets say 24)
2.go to login screen (SDDM) at system settings and apply plasma configurations
3.log out to check if cursor size is smaller than 36
Actual Results:  
The cursor size is always 36 no matter what you set and export at system settings

Expected Results:  
The cursor size at SDDM follows what is set at cursor settings

Tested on F38 and F37 with this package versions:

Operating System: Fedora Linux 38
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.106.0
Qt Version: 5.15.9
Kernel Version: 6.3.3-200.fc38.x86_64 (64-bit)
Graphics Platform: Wayland

sddm-0.19.0^git20230404.e652433-1.fc38.x86_64
kde-settings-sddm-38.2-2.fc38.noarch
sddm-wayland-plasma-5.27.5-1.fc38.noarch
sddm-breeze-5.27.5-1.fc38.noarch
sddm-kcm-5.27.5-1.fc38.x86_64

plasma-systemsettings-5.27.5-1.fc38.x86_64


ADDITIONAL INFORMATION

If CursorSize=24 exists on the themes group at kde_settings.conf, and I change at system settings the cursor to a biger size (like 36 or 48) and then hit the "Apply Plasma Settings" button, the cursor size change acordingly. But if we wanna change the size for something smaller than 36, then it don't apply the change.

Patch idea:
Maybe if we add something like this to this file at the "Theme" group, it will create the right setting => https://invent.kde.org/plasma/sddm-kcm/-/blob/master/src/sddmsettings.kcfg
   <entry name="CursorSize" type="UInt">
              <default code="true">defaultCursorSize()</default>
          </entry>