Sessions of protected networks

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I would like to store captured packets in the database. I think it would be good to sort the packets based on the sessions.

AFAIK only for data packets it is possible to trace the sessions (termination can be filtered by tcp.flags.fin == 1). Because in Wireshark in monitor mode I don't see any data packets. I am using Realtek RTL8812AU WiFi card. Is it wrong card for capturing data packets?

Is it really necessary to have WPA key for protected networks to capture data packets? And there is no chance to trace sessions on protected Access Points?

How can I handle sessions of protected Access Points without WPA key?