You got some nice replies here.
Here’s my two cents on it.
Can you get a speaker-like experience on a headphone? Kinda.
Does it cost a lot? Yes. RAAL SR1a is something you could be looking at for a speaker-like experience.
Can you get a speaker-like performance without leaking sound as much as a speaker? Nope. RAAL’s will leak a lot, but you will be getting that experience. Because the speakers of RAAL’s are closer to your ear, the volume levels would be lower than if you were listening to speakers.
You will need several thousands of dollars to achieve what you are looking for. I simply don’t think you can get something that sounds like a speaker at a budget price. Perhaps the Sennheiser HD800 series, but people said it doesn’t sound realistic and sounds larger than the music is supposed to sound.
I will say that a good pair of IEMs can give you a very open experience, but I don’t think it can be compared to loudspeakers. Spending 500-1000 dollars on IEMs does seem to be a valid option for you. Otherwise, you should go for some ZMF headphones (which are perceived to sound very open, depending on the model).
Hope I helped you out a tiny bit. From my understanding, you will be listening to music at work, and this really limits you as to what product you can use. If you go the IEM way, expect not to hear your colleagues.