The Diatone GT R249+ is my favourite traditional 2.5 inch micro quad based on it's relatively lightweight in this class, motors which have a wonderful mix of power and efficiency, reliable electronics and excellent built quality. My review of this quad is here and it is still available across multiple retailers.
However over a short period of time I started getting a lot of Jello which is concerning given the camera is a CCD which should be much more stable. I did a lot of PID and filter tuning but gave up after a while and let it sit on my shelf. Now I've come back to it with a fresh set of ideas and believe I have fixed the Jello problem once and for all. Firstly I can categorically state that in my case it was not the tune nor the propellers that fixed the issue as I've seen stated elsewhere. The issue is around the camera/VTX and this fix should be relevant to all canopy versions of this quad that doesn't use the TBS vtx i.e.
The screws that hold the vtx to the cam also hold the sensor board to the lens housing and I believe the connection between the board and housing is compromised as a result. At least the Caddx Turbo F2 has some foam tape between board and housing unlike the stock runcam swift although I don't believe a camera change is necessary.