Just a heads up -- on EX4400-48MP, running recommended code (currently 22.2R3), the first port on the switch does not work. We've seen this on all of our EX4400-48MPs with every recommended code release since 21.4. (The issue was not present in 21.2.)
The interfaces start at mge-0/0/1 -- mge-0/0/0 is absent from "show interfaces". There is an et-0/0/0 interface that appeared when mge-0/0/0 disappeared , but it doesn't work.