Helix (and most modellers/emulations) model the impedance interactions, but only for one cabinet. If you change IR’s or cabs, the impedance curve doesn’t change with it. It’s just the impedance interaction they modelled the amp with (usually the matching cab if there is one, sometimes for heavier amps it’s a Rectifier cab).
The only other company I know where you can adjust impedance curves is STL Amphub and their newer Tonality’s.
Profiling will capture what you feed into it. That’s why if you capture an amp direct, the load it’s connected to (and how you intend to use it) is really important