I have an Osmo+ and bought the M1 gimbal.  With newer phones (I have a galaxy note 8) the gimbal either won't work with or is a tight fit.  Due to this I went to an older phone, specifically a Galaxy SIV.  Granted this is an old phone, but it still works.

It works great in the gimbal because of the smaller size, however when doing video it looks like complete garbage.  Photos are fine, but video is awful.  You might say it is a limitation of the phone and the phone takes bad video, but if I use the stock camera program (while in the gimbal) it works fine.  I can provide examples if needed, but why does it work like this.

For the record I did get my note 8 to (kind of) work and the video quality was fine through the DJI go app.

Hi there, sorry for the troubles on using Osmo Mobile, Samsung Galaxy Note 8 is in the compatible list and it should work. Please make sure the gimbal has been balanced properly before powering on.
By the awful video quality, do you mean the video is not stable at all via DJI Go APP? If yes, a short video would be appreciated.