Hello,
There are usually 3 fuseboxes on the Ducato and siblings.
The cab fusebox is generally located around the driver's external knee. Looking at a photo of a 2020 Rapido, it's the same as it was in the previous (2006+) models. There are 2 screws that hold the cover.
View attachment 456967
The second fusebox is located in the engine bay.
The third fusebox is in the bottom of the B-pillar behind another plastic cover:
View attachment 456968
In my case it's the passenger side, but not sure if they moved it as 'knee' one
There are also main fuses in the starter's battery compartment.
According to this
Owners' hanbook (for a 2018 model), the following fuses have A/C in the description (the main fusebox by the driver's knee):
View attachment 456969
View attachment 456970
In the engine bay:
View attachment 456971
View attachment 456973
I don't know if anything has been changed between 2018 and 2020, but it has not been changed since 2011 to 2018