Going to be a problem diagnosing that crash I think.
This a similar sized image in Gimp 2.8.22 - linux and a select - copy - paste-as-new-image works. Although using some of the swap partition which never happens. I have a lot less resources than you. Screenshot: https://i.imgur.com/garOvuc.jpg
You could try increasing the tile cache size : https://i.imgur.com/8GwHTRo.jpg
Do you have plenty free disk space and are you using a fixed disk? Not some usb attached.
Possible work around: Do you know where the 5000x3000 area is? Could you split up the image into quarters using ImageMagick command line? Then work on a smaller image.
This a similar sized image in Gimp 2.8.22 - linux and a select - copy - paste-as-new-image works. Although using some of the swap partition which never happens. I have a lot less resources than you. Screenshot: https://i.imgur.com/garOvuc.jpg
You could try increasing the tile cache size : https://i.imgur.com/8GwHTRo.jpg
Do you have plenty free disk space and are you using a fixed disk? Not some usb attached.
Possible work around: Do you know where the 5000x3000 area is? Could you split up the image into quarters using ImageMagick command line? Then work on a smaller image.