A good BPMN disgram should fit one A4 paper sheet or one computer screen without scroll and still be readable.
Recommended number of activities on a diagram is up to 7, the maximum is 10. If there are more you either have to print it on several sheets and glue them together or scale it down to one page which makes the diagram unreadable.
A recommended approach is to decompose the process into subprocesses and depict each subprocess on a separate page. This way the high-level logic of the end-to-end process is clear while drilling down into subprocesses reveals the details.
An alternative method is to split the process into fragments, depict each on a separate page and connect by link events. This is less preferable because the end-to-end process logic cannot be captured at a glance.
— Anatoly Belaychuk 2024-02-24 18:42