I don't understand the fascination with blur. It's terrible from a security/privacy perspective. The data is still in the image. Sure you can add randomization to the blur to make it less easy to undo(I haven't looked if Flameshot does or not, most don't). If you crop the stuff you want out of the image, there is no data there to do anything with.

Every screenshot tool I've ever come across has a blur tool but no cut tool. So I just use the OS specific screenshoter and then load it up in an image editor and cut to my hearts content.