Hi, I am not sure your swell prediction algorithm is reliable. It seems to be more based on local wind generated wave heights which is not necessarily correct. Intense weather cells remote from the site and resulting wind fetch length and direction are more closely related to swell generation and period.
First of all, waves layers are not a Windy’s algorithm. Windy visualizes the WAM model from ECMWF and the WW3 model from NOAA, which are known as the best global wave prediction models.
The problem probably comes from the fact that you compare Swell and Waves and find little difference between the two.
Waves is the « state of the sea » or the « total sea » i.e. wind waves + swell. Heights from Waves include heights due to the swell.
So to see the difference between local and distant wind effects, it is necessary to compare Wind waves produced by a local wind and Swell produced by a distant wind with a long fetch.
See More layers to get all wave layers.