The presentation of the new specialists in the trailer is a useful reminder that the concept of classes has more or less evaporated in Battlefield 2042.
If you add in the playable specialists from the beta and Kimble 'Irish' Graves (the previously-announced specialist portrayed by actor Michael K. Angel's passive ability lets him revive teammates much more quickly than normal and restore a bit of their armor. By the look of it, swapping loadouts can change which guns and secondary gadgets you're holding, but doesn't change which specialist you're playing.