Budget - $500 CAD with some wiggle room to find the best value point
Source/Amp - I listen to music on my Samsung Galaxy S10e, using Spotify extreme quality(320kbps) with volume normalizer off. I do not have an Amp or DAC and I am wondering if this is the tier of headphones where those become important. I do not know what makes something a good power source so I don't know how to judge the S10e. I have a big amp that is meant for a home theatre system which has a 192kHz 24bit DAC builtin, but it is not ideal for my use case.
Use Case - This would be for home use only. Mostly for music, sometimes for movies, but the music is the priority. In a mostly quiet bedroom, sitting on a couch sometimes, but most times lying in bed, which is why I can't use the big amp.
Preferred tonal balance - I want something accurate and balanced.
Preferred music genre(s) - Mostly rock and hip hop. I really enjoy well mastered songs with a clear separation of instruments and a spacious soundstage, if I am using that term correctly. I want to feel as if the instruments are at different locations surrounding me rather than in my ear. Artists that have impressed me in this regard are Pink Floyd, The Beatles, and Radiohead.
Past gear experience - I've had some Shure IEMs which I used for travelling, upgraded those to some RHA IEMs a few years back. Satisfied with them for their purpose. They provide good isolation and are convenient/comfortable. As far as cans, all I've had are some Audio-Technica ATH-M50's that I bought 10 years ago. What I like about them is the warmth of any string instruments in songs. What I don't like about them is that they are bass-heavy, and I get headband discomfort and sweaty ears during long listening sessions. I am also just very curious about how much better the spaciness/soundstage can get.
I've done some research and am leaning heavily towards Hifiman Sundara's. Right in my budget, planar magnetic seems cool, I like the look, the headband looks comfortable, and based on reviews it has the sound profile I am looking for. But I was only choosing based on headphone, I wasn't thinking in terms of complete setup. Would it be a waste to get these headphones without some sort of Amp/DAC setup? Do I need one, both, neither? Would a balance of budget between headphones and Amp/DAC result in an overall setup that is better than if I were to max the budget on the headphones and get no/cheap Amp/DAC?