Windows 11 on arm64 can run x64 programs, however npcap currently only installs x86 and arm64 libraries, so x64 programs can't load wpcap.dll. Another problem is that there's no separate System32 directory for x64 (unlike for x86).
I was able to get x64 Wireshark to capture packets on my Arm64 Windows 11 by copying wpcap.dll and packet.dll from an x64 system to Wireshark's installation directory.
Windows 11 on arm64 can run x64 programs, however npcap currently only installs x86 and arm64 libraries, so x64 programs can't load wpcap.dll. Another problem is that there's no separate System32 directory for x64 (unlike for x86).
I was able to get x64 Wireshark to capture packets on my Arm64 Windows 11 by copying wpcap.dll and packet.dll from an x64 system to Wireshark's installation directory.