How to include tax in displayed product prices?

Yes, you’ll need to update the prices of all products/variants to include taxes, as the displayed price should be the total amount including taxes. This may be a cumbersome process, but it is necessary to ensure accuracy in pricing. Updating cost per item may affect your profit figures, but this will reflect the true cost of the products including taxes. You could consider using a spreadsheet or a bulk editing tool to make this process more efficient.