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

https://www.save-bookmarks.win/planning-a-gaming-setup-in-limited-space-means-smart-choices-start-with-a-desk

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