Finally, a month after buying the first drone, I couldn't find an abnormal solution to an emergency landing on water, so I did it myself. For those who don't want to buy it in China:

Pool needle – 16 cm x 32 mm. Half of noodle.
https://www.thingiverse.com/thing:6614722
Cutter for this.

Use styrofoam parts so that the drone can land on the water. Do not worry, no additional foam parts are required - the Mini has a problem with wind resistance and when landing on water there is a chance that it will turn over if there are more than 2 foam skis. For this reason, I did not make the wings in a different configuration.
Thing with name "pool float" too big for Mini. Pool foam better choice at Air, Pro and others Mavic models.

This variant may be like thin version, like fat version.

You need 2 little no-magnet screws or superglue for good for better contact of the wing with the base. This is optional, the parts hold together quite well.
Add some photos later, but if need, send me a message.