Hi Ian,
Please refer to the "Log errors to a console" section in the linked documentation. You will want to follow the steps that describe how to save the log to a file and then you can upload it here.
Troubleshoot—Survey123 for ArcGIS | ArcGIS
Also, please include the external CSV that you are referencing for your Pulldata calculations.
Upon first look, it seems that you could benefit from utilizing 'external selects', considering that it appears you are using cascading selects and have over 8,000 choices in the choices sheet.
You can reference the documentation here for information related to external choices and how they can lead to enhanced performance
Cascading and external selects—Survey123 for ArcGIS | ArcGIS
Best,
Brandon