Hello Ale,
Greetings!
Thank you for reaching out to this forum. As a fellow Microsoft user, I'm here and ready to help you out today.
I understand your concern as the Data visualizer template is missing in the Visio version.
The ability to use the Data Visualizer templates is only available with Visio Plan 2. If you're not sure what version of Visio you're using, select File > Account > About Visio.
Kindly verify Professional 2021 falls under which plan in below link.
https://www.microsoft.com/microsoft-365/visio/microsoft-visio-plans-and-pricing-compare-visio-options
To enable Data Visualizer commands in Visio, please try below options,
On previous Visio builds, the Create, Refresh, and Export commands are available in the Create from Data group on the Data tab in the ribbon.
On Visio builds 16.0.9029.2040 or later, the Refresh Diagram, Update Source Data, and Export commands are available in the Data Tools Design ribbon tab.
Please refer below link for additional details.
https://support.microsoft.com/office/e1273f3a-eafb-4e70-ada1-900fca4629c0
Hope this information would be useful to you. Please feel free to get back if you need any additional info.
Thank you!
Ravikumar
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