When listLayers is used to list all the layers in a Map within a ArcGIS Pro-project, all the connections are validated.
When a lot of connections are broken, this can take up a lot of time. In my use case where an Oracle database server cannot be reached, it seems to take about 2 minutes per layer.
My idea is to add "validate = False" as an option. This should then disable the validation of the layer connections.