Macbooks have a very productive optional function: they can announce the time every 15 min.
I've created a similar function where you can personalize the interval (block 6, by default 15 min).
The alert is set to inexact mode to save battery, which means the alert may be delayed by 0 to 3 min, but this can easily be changed to exact mode (block 16).
🛡️ No special rights.
🆓 Suitable for non premium (13 blocks).
Rate and review within the app in the Community section.