Trying to re-create a previous photoshop gradient...

Try doing it in stages using more than layer, as c.p. suggested

Fill a layer with the purple background.

There are so many ways you can proceed from here, but lets look at the gradient tool to start with.

With white as your foreground colour, select the gradient tool, and in the Options Bar choose the second option, Foreground to Transparent.

Drag the gradient from the centre of the screen top the bottom of the screen.  It is important not to go too far, or you'll have a hard edge if you need to modify the gradient

You can Free Transform the white gradient layer to any shape you prefer

You can use Gaussian Blur to soften the gradient

If that makes the gradient too thin, you can copy the layer.

If that makes it too dense, you adjust layer opacity

Or  you can practice with the Gradient editor, which is a very useful skill to develop

Switch back to the first option, which is Foreground to  Background.

Click on the gradient to open the editor

Click on either of the end stops (red highlight) which create a central slider (green highlight)

Drag the central slider to change the gradient

or

Or you can click under the gradient to create a new colour swatch

With the new colour point active (a black triangle above it) select a colour either from the swatch panel, or click on the image

Or go crazy.  If you make something you like, save it by clicking on New.