For people over 40 years old, notifications are impossible to read. Maybe the designers of Garmin watches didn't know that humans when they are older than 40 years old, they start suffering Presbyopia which is an age-related condition where the eyes loose the ability to focus actively on nearby objects.
So, a Garmin watch is completely useless for somebody over 40 years old. If it is a sport watch, it is not possible to carry your glasses to be able to read something on your watch.
Is it so complicated to add the feature to customize at least the font size on the notifications on a future os update?