I was thinking about this for a while. Because for some IEMs when i try to insert them deeply volume is reduced. It might sound better but is it always the best?

Currently I am using the standard Samsung In-Ear Headphones (see picture). My problem is that I am already using the big eartip (L) and I do not get a proper seal. How do I get them deeper into the ear canal?

Looking for best isolating (passive) universal IEMs, hopefully deep inserting and definitely with a replaceable cable (MMCX preferred). What choices are there? Shure SE, Westone W and UM pro fit Comply P-series foam tips. I have never worn any universal that blocks more than these babies...