The golden rule for bedside tables is comfort. Aim for a height that sits 5 to...

https://www.normalbookmarks.win/ideally-your-bedside-table-should-sit-5-to-10-cm-below-the-top-of-your

The golden rule for bedside tables is comfort. Aim for a height that sits 5 to 10 centimetres below the top of your mattress. This keeps your lamp and phone within easy reach while you are in bed