Aim for your nightstand to sit level with the top of your mattress or just 5-10...

https://amumreviews.co.uk/should-bedside-tables-be-higher-than-the-bed/

Aim for your nightstand to sit level with the top of your mattress or just 5-10 cm lower. This creates a natural reach when you’re tucked in and keeps your essentials within easy grasp. Most standard bedside tables fall between 55-70 cm high