Hi @guekjcow,
Based on the issue that you mentioned, do you want to add new columns to your data source in Power Apps?
Could you please share a bit more about your scenario?
Actually, if you want to add new columns to your Dataverse table within Power Apps, I am afraid that there is no way to achieve this directly in Power Apps.
The functions that this Power Apps has don't modify the original table. Instead, they take that table as an argument and return a new table with a transform applied. See working with tables for more details.
You have no choice but to add new fields to your data source side.
Hope it could help you at some degree.