Original Problem: Not able to change the default alarm sound in the Google Clock app.
This is a bug in the Google Clock app itself, and probably not the fault of Samsung.
This used to work correctly in the last major version 7.x series, but broke when they moved to the current major version 8.x series. I tested and found that you can set the default correctly in Clock version 7, but once upgrading to Clock version 8, a bug in the app no longer allows you to do so, and you're stuck with whatever default was last set in version 7. I tested this solution in both an old Realme phone and my new Samsung S23 Ultra as well - working in both devices.
SOLUTION! (To be clear: This is a workaround. It doesn't fix the original problem, but allows you to set a default alarm sound by rolling back to an older version of Clock app.)
1. Install APKMirror Installer (Official). 2. Download the latest version of the Google Clock 7.x series from APKMirror. At the time of writing, it is Clock version 7.14. (Choose the closest matching variant, or try a few. If you want to be extra sure, you can go to the FAQ page and install "My APK", then search for "Clock" in that app and look at the SHA-1 signature at the bottom. The first 4 characters without colon should be the one you look for in the variants list. Any variant with that signature should work, so you can pick the largest DPI range with it.) 3. Uninstall currently installed Google Clock completely.NOTE: Take note of your customized settings, alarms etc. You'll lose everything. 4. Open the downloaded file in APKMirror Installer and install it. (You'll have to give a few permissions like storage access and install from unknown sources. Also on Samsung, you may need to disable Auto Blocker. All these will be prompted to you.) 5. Open the Clock app and set an alarm. Set the sound you desire as the default. (It can be your own sound file and doesn't need to be a device sound.) 6. You can test by deleting the alarm and setting a new alarm. You should see that your chosen sound is the default. As long as you stay on Clock 7.x whichever sound you choose last will become the default. So make sure you have chosen the sound you want as default before next step. 7. Open the official Google Play Store app and update the Google Clock app. (It will update to 8.x series which is the latest as of now.) 8. You can test in the updated Clock app that any new alarms set will get the default you had already chosen in 7.x series, and choosing another sound will NOT change it. It will also not reset to the Homecoming sound unless you clear data or uninstall/reinstall the Google Clock app.
As a bonus step: Please open the panel to choose the sound of the alarm, then tap the three dots on top right corner, and tap on Send Feedback. Type in your complaint, add a screenshot and send a feedback to Google. (Mention that it used to work in version 7 but broke in version 8. Sample below:)
> In version 7 I could change the default alarm sound by simply setting a new sound in an alarm, and all new alarms pick up that same sound. But in version 8, this broke and the default alarm sound is always the one the I had last set in version 7 or the one that the Clock app started with the first time. There is also no setting in the Settings panel of Clock app to change the default. Please fix ASAP.
The more people send a complaint, the more likely Google is going to do something about this. Perhaps one day it will be fixed in the 8.x series or at least in the next major version.
