Quick answer: Yes. Apple says alarms created in Clock still sound when Silent mode, Do Not Disturb, or another Focus is on. The alarm's chosen sound and the Ringtone and Alerts volume still matter.
Silent mode does not mute a Clock alarm
The Ring/Silent switch, Action button Silent mode, and Focus modes are designed to quiet calls and notifications—not a scheduled Clock alarm.
What can still make an alarm seem silent
Silent mode is usually not the culprit. Check the alarm's enabled switch, chosen sound, Ringtone and Alerts level, AM/PM time, repeat days, and whether you edited a Clock alarm or a separate Health sleep schedule.
What happens with headphones
Apple says the alarm uses the built-in speakers as well as connected wired or wireless headphones. Test your own sleep setup if headphones, Bluetooth speakers, or a charging stand are part of the routine.
Where Ransom fits
Ransom is not needed merely to make Silent mode work; Apple's alarm already handles that. Ransom is for the next problem: requiring deliberate action after the sound begins.