Npcap versions 0.95 through 0.995 had an uninstaller problem where they didn't always correctly remove the "Npcap Loopback Adapter" that the installer creates. So systems could collect extra versions, ...
I used the Npcap 0.99-r6 installer and ticked the options for the loopback adapter and compatibility mode. Also reinstalled Wireshark to make sure it recognizes Npcap (it previously used WinPCap, but ...