Yes, FixMySpeakers is a legitimate app that really does work!
As one can see on the product's site, the FixMySpeakers app plays a specific tone which generates sound waves causing the water to be expelled from the device.
FixMySpeakers was the #4 Product of the Day on Product Hunt on February 24, 2019.
Mentioned in this answer
FixMySpeakers
Eject water from your phone's speakers after getting it wet