No The long answer: as the plug is a microphone connection, which is not available on the smartphone in this configuration, the microphone on the mobile cannot be used without an adapter. Don't be confused by the fact that the plug is a 3.5mm connection, which is also used for headphones and headsets - this is about the assignment of the channels/pole/sectors - the smartphone needs a TRRS plug to be able to receive a microphone signal at all (TRRS is the plug with 3 (black) rings). Whether the sound quality is better than the microphone in the smartphone naturally depends on the smartphone and what is to be recorded.

I think so, that shouldn't be a problem. The Oslo Pocket adapter just allows the connection for a 3.5 jack. See original text: The jack plug adapter allows an external microphone to be connected to the Osmo Pocket. --> this FlexiMic is just such an external microphone, which massively improves the sound quality. :-)

This microphone is not recommendable at all!

The way it looks (google images search), the mic is plugged directly into the mobile phone in use with the DJI Mobile 2. Then I would suggest another mic, because otherwise the FlexMic points to the side instead of to the front! BTW: The FlexMic has only mediocre sound quality. I use it with the DJI Osmo gimbal.

The Micro also works with the Osmo Mobile. The mobile is operated with the DJI go app.

Have you ever asked this question to Mrs Google or Mr Youtube?

Yes, this also works on the PC. However, I would recommend a USB micro.