The shape list in Miro seems to be pretty complete with regards to the BPMN 2.0 standard.
What is missing though is the default sequence flow indicator on the connecting flow arrows following after a gateway. They are thoroughly used by process engines and described vastly i.e. here.
I was trying to port some diagrams from Camunda Modeler to Miro and fell short on this particular feature.

The little / indicator for the default flow is missing in Miro.
For process engines, this feature is mandatory. This might not be the case for diagrams in Miro, as you can express it with text. But it is a potential source of bugs, when using Miro-based BPMN diagrams in process engines.
