I appreciate the immediate reply, @raes88.

Thanks for confirming that you're using QuickBooks Desktop Enterprise. I'll share other troubleshooting steps to remove the subtotal and Grouped Items Subtotals on your estimates. 

Either sales tax is turn on or turn off, you're able to remove the subtotals on your estimates. Since you're unable to see the subtotals in the footer section, I'd suggest going to the Lists to the item inactive. 

Here's how: 

1. Go to the Lists on the upper left side. 
2. Choose Item List. 
3. Hover the mouse to the Subtotal, then click the Item drop-down arrow. 
4. Pick Edit Item. 
5. Put a checkmark on the Item is inactive.

After that, go to the estimates to check if the columns are invisible. 

But if you're referring to the subtotal line item that you add when creating the group of items, we're unable to hide this. 

I've added an article about managing items in QBDT: Add, edit, and delete items. 

If you need anything else, please let me know, and I'll get back to you.