Start by measuring your available space and aim for a desk about 100 to 120...

https://www.bookmark-suggest.win/planning-a-gaming-setup-in-a-tight-space-starts-with-choosing-a-desk-about-100

Start by measuring your available space and aim for a desk about 100 to 120 centimetres wide to fit your gear comfortably. Use a monitor arm to free up desk surface and improve screen positioning