A non destructive way, allowed by a new layer mode in Gimp 2.10:
- Put the text and its background (red disc) in a group
- Add a layer mask to the text, init to white and render a turbulent plasma in it
- Set the text layer blend mode toErase. This makes it act as an anti-mask on the image below, so the opaque part of the text will make its background transparent, and the image background will be seen
- Add some contrast to the mask (used Curves, but Brightness/Contrast and Levels are also possible)