Hi SameerColbert,
You can change the timer sound by opening the Clock app and tapping the Timer icon at the bottom. From there, tap "When Timer Ends" and select your preferred sound, then tap "Set". After you've made the selection, test it by asking Siri to set a timer to see if it plays the sound you've selected.
If the issue continues, restart your iPhone. Although simple, this step can help correct some unexpected issues. It's also a good idea to make sure your iPhone is running the latest version of iOS 17, since this can help with overall performance: Update your iPhone or iPad
If an update is available, be sure to create a backup before installing it.
1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. If you see more than one software update option available, choose the one that you want to install.
5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.
You mentioned that when you ask Siri to set a time, "Siri proceeds to set the alarm". If Siri isn't recognizing your requests accurately, there are some additional steps that may be helpful here: If Siri isn't working on your iPhone
Regards.