If you don’t want to deal with the particularities of setting up all the different aggregators, take a look at this: https://discussions.flightaware.com/t/a-simple-way-to-feed-ads-b-data/90183
It’s as simple as setting the feed key for each aggregator in the webinterface.
Edit: you don’t need a pi5 to run the airspy, pi4 will do fine.