Planning a gaming setup in limited space starts with a desk about 100 to 120...
https://tango-wiki.win/index.php/How_to_Game_from_Bed_Without_a_Permanent_Setup
Planning a gaming setup in limited space starts with a desk about 100 to 120 centimetres wide to fit your monitor and accessories comfortably. Use a monitor arm to free up surface area and create more room for your keyboard and mouse