The golden rule for bedside tables is keeping the top surface between 5 and 10...

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

The golden rule for bedside tables is keeping the top surface between 5 and 10 centimetres below your mattress top. This makes reaching for your phone or a glass of water feel natural rather than a stretch