Building a Circle visual (not a KPI one) with colour conditional formatting

In that case you can try this alternative method :

1. Create new measure 'Full Circle Measure'

DAX 
Full Circle = 1

2. Add a Donut chart visual to your report canvas & Drag your new Full Circle measure into the Values field of the donut chart. It will now display a solid, complete circle.

3.  Slices: Change the color to the shade of green you want.

Spacing: Adjust the Inner radius to create the hollow circle effect. A value around 80-90% works well.

Turn off unnecessary elements: Disable the Title, Legend, and Detail labels as you won't need them.

4. Insert a Card KPI in the centre of donut 

Format the Card:

Turn off the Category label.

Adjust the font size and color of the Callout value.

Under General -> Effects, turn the Background off to make it transparent.