This is in the Google Clock settings. It's the snooze length that is buried deep down, that you're meant to set once, and it applies to all of your alarms.
I know what it is.
You're acting like it's something you need to do every time you set an alarm. That's not true, and until you were called out for it, you kept all of your replies vague to make it seem like it's something you had to do often.
I didn't even know the UI existed until I went looking, since you ignored my other comment asking which app this was.
And a slider is a bad design. When I'm trying to choose a password length in my password manager using a slider, I can never pick the exact number. It jumps as soon as I let go of the button.
Now imagine that garbage when trying to change the snooze length?
To be fair, this is for setting the duration of the snooze button for your alarms, not a timer. Most people would set it once and never touch it again. Anyone snoozing for more than 30 minutes is a psycho that hates sleeping anyway.