This is an alternative bed mesh image to complement the profile update plugin published by Toylerrr as https://www.thingiverse.com/thing:4899915 for Cura 4.11.
After installing the plugin in the Thing above, locate your Cura meshes folder which should be in (on PC Win10);
This PC>[Boot Drive Letter]:>Users>[your user ID]>App Data>Roaming>Cura>[target version number]>meshes
Rename the current Neptune2.stl as .old in case you need to revert then paste the new STL provided.
Enjoy
Edit:
The plugin will work in version 4.12.1 but you may get a configuration message error when you restart Cura. It seems it does not like bringing over the config data from the previous version
The info below assumes you have not yet un-installed the previous version of Cura that you were using (in my case 4.11).
If you have not set up any other printer profiles in the previous Cura version then you can:
Choose the "reset" option offered in the error message. THIS WILL DELETE ALL PRINTER CONFIG INFO AND PROFILES.
Restart Cura 4.12.1 to ensure errors have gone.
Re-install the Toylerrr plugin and restart.
Add Elegoo Neptune2 printer and restart.
OR If you have set up any other printer profiles in the previous Cura version and do not want to lose them using the "reset" option
First, backup your definitions, extruders and meshes folders in your AppData/roaming>Cura>[previous Cura version] folder (to be safe (they should all still exist in this folder if as you will be editing the 4.12.x folder.))
Then delete any reference to neptune2 in the AppData>Cura>4.12.x; definitions folder extruders folder meshes folder
This should hopefully allow you to preserve any other printer configs you wish to keep.
Restart Cura 4.12.x to ensure errors have gone.
Re-install the Toylerrr plugin and restart.
Add Elegoo Neptune2 printer and restart.
NOTE: I would advise always keeping your previous stable and working version of Cura installed until you have tested and are happy with the performance and stability of a newly installed version.