WiFi Direct is indeed a P2P connection, but not much else. The APIs are still there, but you can’t manage it easily through the UI anymore. And honestly, it never really made sense to do that, anyway. Connecting is just step one, you need additional software to actually use the connection once it’s been made. There is no “standard” for transferring files over WiFi direct like there is with Bluetooth.
Many years ago, some phones had “WiFi Direct” as a sharing option that used some proprietary protocol. Worked great on device that shared the implementation (mostly Samsung-to-Samsung, I think), but support was removed at some point. It was never really a standardised mechanism, even though it worked really well.