Hot water heaters don’t work like this. Sounds like you have something wrong with the hot water heater itself.

When you first use it the water will be at the hottest point. As you continue to use the temperature will slowly go down to a certain point where the heating element can keep up with the water outgoing.

I’d get the it checked by a plumber. May need to replace heating element or the hot water heater itself.

Dude, like can you just set a reminder on your phone? Seems like an easy fix.