I have a brand-new install of GIMP. I ran it once and then went to install GMIC. I ran the isntall but GMIC won't appear in my menu, and I get an error when GIMP tries to load. It appears when it queries new plugins.

The error reads: The procedure entry point g_memedup2 could not be located in the dynamic link library C: Program Files GIMP 2/bin/libgobkect-2.0-0.dll

Uninstall Gimp and uninstall G'mic Install the latest version of Gimp (2.10.24) then install G'mic 2.9.7
pay attention! Last dev (see picture)

You may need to tell it where to look by putting the path in preferences.

Might be easier to help you if first you let us know what OS you are using.
Windows? Mac Apple? Linux? and which one

Or you could go here https://www.partha.com/ to download another gimp. Partha's builds often come with gmic but unfortunately it wont be the latest version. They are 2.10 but not the latest.