How long would you say is appropriate for a nap?

I am a fan of science....and power naps.

The Science of a Perfect Nap

Power Nap: 10 to 20 minutes. Most sleep experts agree that if you want to have a quick jolt of alertness and vigor and/or decrease fatigue, take a 10- to 20 minutes.

Grogginess Nap: 30 minutes. Some studies have shown that when you take a longer nap, the effects of sleep inertia begin settling in after you wake up.

Short-term Nap: 60 minutes. We all know that somewhere between 30 to 60 minutes is when we start to graze the surface of our deep sleep cycle.

REM Nap: 90 minutes. And finally, we have REM (rapid eye movement) napping. This when you have reached your full sleeping cycle and dream.

REF: https://www.scienceofpeople.com/how-long-to-nap