I've found IEM-style headphones are better. Since they already block out some of the ambient noise by plugging your ears, much lower volume levels are required to block out distractions.
Besides I really enjoy just silence sometimes, being forced to listen to music does not necessarily improve my focus.
And I work in my own private corner office.
There also exist on-ear headphones that don't apply so much pressure. So it rather seems to me that the model that you tested simply does not fit your requirements.
I also prefer over-ear over on-ear, but did not have the problem with on-ear headphones that you described.