"I want that as a preset, NOT as a brush preset."
That makes no sense. A brushed-in local adjustment is applied to a specific, restricted and usually irregularly shaped area within the picture. Once applied it can't be moved. If it were included in a general Develop preset, how could you assume that in any future photo the placement would be appropriate? Graduated and Radical filters can be in a general preset (as well as having their own local adjustments preset) because they can be dragged to a new location if their placement does not fit the photo, but this cannot be done with a brushed adjustment. So save the settings you have now in the brush panel as a brush preset, then on another photo open a Radial Filter and apply the brush preset to it (it will appear in the presets list for the Rad Filter also). If you want the effect to cover the entire image area, invert the mask and expand the circle until its boundaries are outside the image. Afterwards make a new Develop Preset that has the Rad Filter box ticked.
I see two choices for the OPs question-
1. Save as a brush preset (I know this is NOT what you asked, but read on!) . And use the GRADIENT filter to apply the preset across the entire image. ie. Drag the gradient cursor totally across the image, starting with the cursor outside the edge of the image. and repeat to double the effect!
2. Make a note of all the slider settings for the Brush settings, Apply the same slider settings in Develop (without a brush active), make a regular (global) preset.
Everything you do in a brush is available somewhere in the develop panels.