For me the solution was
have a multimedia keyboard connected to the system. Only a usb dongle for a multimedia keyboard is enough. Then the Targus media remote would work with all buttons. And secondly, the remote will not work at all when logged in to the system over remote desktop. Since the media keyboard and media remote then are entering key presses to the login screen only. With TeamViewer instead of Windows Remote Desktop (rdp) it would work even when connected remotely.
AND.... the Targus remote didn't connect reliably to the ECS LIVA built in bluetooth. I didn't dive into fixing that but instead took an old USB bluetooth dongle I had lying around and bam, all works finally.
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Regarding Apple media remote. I found that it's hardware is compatible with the Windows "eHome" receiver, the normal WMC IR receiver. This according to this site
https://www.iospirit.com/products/remotebuddy/hardware/Now you "only" need to find some similar software for Windows. I would look at AutoHotKey and whatsamacallit... ghostevent? Can't remember right now if that's the correct name.