How do you display 2 testimonials in one widget

If using premium, see How do you show multiple testimonials in rotation?.

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It's not possible unless you're using the Testimonials Widget list shortcode or theme function.

Instead, "stack" the testimonials widgets in your widget block. Make sure to remove title of the bottom and select "Prevent duplicates" in each of the widget options. Also, set "Limit" to 5 unless you have more than 20 testimonials. If not, you'll see the dreaded "No testimonials found" notice.

See How do you show multiple testimonials in rotation? for more explicit guidance.

The `unique` AKA prevent duplicates capabilities are a part of Testimonials Premium. Purchase the premium plugin.