I wanted to backup the vst intrument files but I see that MM2023 don't do it in the " C:\Users\you\Documents\MAGIX downloads\Installationsmanager " anybody know where, thanks.
The installed location of Magix VSTis is C:\Users\Public\Documents\MAGIX\Common. Within that location you will find folders such as Live Pads and Mx Synth.
I don't think the actual installers for these are saved anywhere on your computer. But you can, clearly, back up those listed folders to ensure you have a safety copy of them all.