With my case of ADHD, my brain will easily shove a notification to the background if I don't expect it or if the notification sound is happening too often. My threshold for "too often" is very low.
So, I use alarms sparingly. They break through my ADHD, and this is a #hack I use to set future alarms and it's pretty simple:
Have a timely event that must happen more than 24 hours from now