What makes a good architecture sketch?
One box per part, one arrow per connection, and every box named after something real. Fitting on a single screen is a useful discipline. If it does not fit, you are drawing two diagrams at once. Level of detail matters far less than completeness at whatever level you chose.
From From whiteboard sketch to working software, published 9 August 2026. That article is where the reasoning behind this answer is set out, including what it does not cover.