Looks like using command line ImageMagick is not favoured 
I see the post on Reddit.
Davids Batch Processor (dbp) This was for Gimp 2.8 and earlier, there is a 64 bit Windows version but I cannot get it to work with Win10 / Gimp 2.10.22 So stuck with the original 32 bit plugin. The web site is long gone, get it from the Internet archive.
https://web.archive.org/web/201211140908...-1.1.8.zip
Unzip and put dbp.exe in C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\plug-ins
In use:
Input Tab: load the file list
Rename Tab: Tick Flatten
Output Tab: Select PNG, untick the options (especially Interlacing) Click the Start Button.
An animation of all that. 64 bit Win10 / Gimp 2.10.22 https://i.imgur.com/Jdg3AnG.mp4
I see the post on Reddit.Davids Batch Processor (dbp) This was for Gimp 2.8 and earlier, there is a 64 bit Windows version but I cannot get it to work with Win10 / Gimp 2.10.22 So stuck with the original 32 bit plugin. The web site is long gone, get it from the Internet archive.
https://web.archive.org/web/201211140908...-1.1.8.zip
Unzip and put dbp.exe in C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\plug-ins
In use:
Input Tab: load the file list
Rename Tab: Tick Flatten
Output Tab: Select PNG, untick the options (especially Interlacing) Click the Start Button.
An animation of all that. 64 bit Win10 / Gimp 2.10.22 https://i.imgur.com/Jdg3AnG.mp4