@ David Tschumperlé
Maybe you can check this out, seems to be a re-occurence of missing files in the latest Windows Gimp 2.10.34 - version 3 dated 13 August.
Using the gimp_gmic_qt 3.2.6 Windows installer gives errors for missing files libicuin72.dll and libpcre2-16-0.dll there is a bit qbout it here. Where is G'MIC?
Is it gmic or is it for the Gimp dev’s ?