Depends how you installed it. Officially there is no support for processing on the RaspberryPi4, and future support will likely be for 64 bit. Currently I am successfully running Sam Pottingers development version of Processing4 on Manajaro ARM [64 bit] see here, and wiki entry. See original processing for pi here. If you tell me how you installed processing, I can give specific advice. The problem with duplicate libraries is most likely a processing thing, and how libraries get loaded (libraries are stored in ~/sketchbook/libraries) and nothing to do with a duplicate installation of processing. If the processing ide detects libraries requiring/providing duplicate jars/resources it throws a wobbly. This a case of convenience over usability.