A few things for Windows:
1. C:\Users\(USERNAME)\AppData\Local\gegl-0.4\plug-ins this is a localization for all versions of Gimp (except for the portable version Gimp-2.10 samj).
2. ... lib\gegl-0.4\plug-ins\ is the localization for a specific version of Gimp.
3. If users of both Gimp-2.10 and Gimp-3 placed the files Official GEGL Bevel.dll and Official GEGL Inner-Glow.dll in the C:\Users\(USERNAME)\AppData\Local\gegl-0.4\plug-ins directory in Gimp-3 they would be loaded twice (from that directory and as a built-in plugin), which is not a good practice.
4. The choice of the name of the 'plug-ins' directory may not have been the luckiest (because it was used for the third time), but let's leave it that way (although instead of plug-ins it could be named anything you want, e.g. WindowsBinaries and/or vibe_coded_windows).
5. Compiling two Gimp plugins takes very little time, so I wonder why you waited?
