QB Issue Resolution:

Try a new tax rate and scroll down if you do not have Purchase tax option then the version you have does not work for Vat. Its possible you have a sales tax international version or US version

Resolution for Issue 'How to add multiple tax rates to one Tax Authority' available: Yes (Solved).
Source: Intuit Community forum.

How to add multiple tax rates to one Tax Authority: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.

Support for purchase tax
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Error Recovery for purchase tax [Canada]
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