Fiido D2: shock absorber broken
Your best bet would be to contact the manufacturer for specifications or even replacement parts. Failing that, your next best thing should be to measure/learn parameters of your current shock, and then finding another ones that matches closely these parameters.

What you need to measure/find out are:



Eye-to-eye length
Stroke length
Mounting hardware used to mount it into the frame and related parameters. such as diameters of mounting holes
Air pressure or coil firmness values


See e.g. this article