05-07-2022, 10:35 AM
(This post was last modified: 05-07-2022, 10:36 AM by rich2005.
Edit Reason: typo
)
Another way, equally hands on 
Make a text layer
Rotate the text layer.
Using the text as a separate image, reduce the opacity.
Export the image as a png to your patterns folder.
In the image to overlay, refresh the patterns
Bucket fill using the new pattern,
Might go like this: https://i.imgur.com/eTXLndz.mp4
If you want a plugin with variable text / size / etc... Then the Gimp gmic plugin has a 'Visible Watermark' filter.

Make a text layer
Rotate the text layer.
Using the text as a separate image, reduce the opacity.
Export the image as a png to your patterns folder.
In the image to overlay, refresh the patterns
Bucket fill using the new pattern,
Might go like this: https://i.imgur.com/eTXLndz.mp4
If you want a plugin with variable text / size / etc... Then the Gimp gmic plugin has a 'Visible Watermark' filter.