I installed JetStreams on my Rocket 3 GT, MY 2023 in late 2024. After straight installation without i.NEX I got error messages from the system and the indicators wouldn't work. Purchased the i.NEX and after installation it worked. Flawless until now for the last 14 months.
Placed the i.NEX under the seat, as it asks for direct battery connection. Needed to pull cables from the front indicators to the seat and back again. Annoying, but doable. The module itself was placed in a plastic bag (splash-proof) under the seat and that was it. The work itself took two long afternoons on a rainy weekend. Removal of the fuel tank was not necessary; used plastic straps for "invisible" wiring beneath.
Judging by A1A Riders remark, it seems that the latest Storm Edition works without i.NEX. Good for you