I don’t use Android or Samsung phones but it’s possible they have some DSP audio enhancements turned on that you like the sound of? iOS doesn’t really do anything like that.
If the Samsung’s headphone jack has high output impedance, it’ll give the Sennheisers a bit of a bass bump, which many people like. EQ (unfortunately not many options for that on iOS, besides an outboard device like the Qudelix5K) or an impedance adapter between the dongle and headphones can produce the same effect.