For the perfect setup, aim for your bedside table to sit roughly 5-10 cm below...

https://lilyluxemaids.com/the-golden-ratio-of-bedside-comfort-matching-your-mattress-to-a-60-63-cm-nightstand/

For the perfect setup, aim for your bedside table to sit roughly 5-10 cm below the top of your mattress. This makes reaching for your phone or a glass of water comfortable rather than a stretch