My setup: Xbox Series controller, bt2usb 1.8.0 on Pico W, XInput output mode

It looks like rumble effect is not being applied properly compared to "native" XInput connection. The best I could describe it is that the effect is generally applied with higher intensity and for much longer time.

I was testing these comparisons with Xbox Series controller on PC (connected through official wireless adapters) and wired 360 controller when testing on Xbox 360. I also tested this in multiple games on both PC and Xbox 360, so I don't think this is game specific issue.

As an example, in Assassins Creed Brotherhood, when you jump and land from high ground, the native connection generates very short (under a second) subtle "thump" effect. But when using bt2usb, it's full intensity effect lasting 3 or so seconds. Similar with Stalker 2, shooting one bullet from a gun normally generates short rumble effect, but with bt2usb it's full intensity long lasting effect.