Hey there, ap-rhwilliamstru.
I appreciate you taking the time to reach out to the Community for support. I'd be happy to provide some information.
Once sales tax has been set up, there isn't the option to disable it. I can see how being able to disable taxes would be beneficial for you, so I suggest leaving feedback for our developers. Comments are viewed and considered as they create new features and updates for the software. Although you cannot disable taxes, you can delete sales taxe rates and agencies by following the steps in this guide.
For assistance with migrating from QuickBooks to Sage 50, you'll need to reach out to the Sage support team.
If you have any other questions, feel free to reach back out.