I appreciate your proactive approach in addressing the issue of the new sales experience, @Envisioner. I’ll make sure you’ll be able to switch to a modern template so you can perform the workaround.

To change the template of your estimate to Modern, you can open an existing or new estimate and click on the Manage icon. Then, select the Design drop-down and enable the Modern template.

I've included a screenshot for your reference:

You can also set the Modern template as the default by clicking the Make Default option in the Design drop-down. It automatically switches to the Modern template mode whenever you open a new estimate.

I would recommend reaching out to our support agents. They will securely collect your contact information and add you to the list of affected users to ensure you receive email updates about the issue.

You can follow the steps below to reach out to them:

1. Sign in to your QuickBooks Online account.

2. Click on the Help button.

3. Select the Search tab.

4. Choose the Contact Us option below.

5. Select Customer and vendor payments as a topic, and then choose a way to connect with our banking team:

• Start a chat with a support expert.
• Get a callback from the next available expert.

Kindly consider checking their available hours since they can only accommodate you Mondays to Fridays from 6 AM to 6 PM PT and Saturdays from 6 AM to 3 PM PT.

I've included an article that guides personalizing and adding specific information to your sales forms: Customize invoices, estimates, and sales receipts in QuickBooks Online.

Furthermore, if you need help closing out your books by reconciling your payments and entries, I'll share this article with you: Reconcile an account in QuickBooks Online.

I'm all ears and ready to help again if you have more concerns about sending estimates. You can also add any other questions about other areas in QuickBooks Online. Always here to help.