1.) The "Brightness" option needs to be removed. This is because Opacity does what is required.
2.) Please set the default Blur to "2" for all users. This would make the Spotlight feature feel like a true spotlight upon default first use and users can always freely have the option to turn off the Blur by setting it to "0"
3.) Please add a Shadow effect option (enabled by default) that would show around the inside border of any drawn spotlight
4.) Please add more drawing shapes, mainly Circle and a Rounded Square. A true rounded square as in a Squircle as seen in app store's of Apple or Google
https://en.wikipedia.org/wiki/Squircle
To help facilitate more drawing shapes - I think it should be presented as a drop-down menu button with icons. In addition, I think double-clicking on the drop down button could then cycle through the available shapes
an example of a drop-down menu with colourful icons within latest XnView MP
========================Having the default Blur set to "2" does work