I also like earbuds with passive isolation. I am obsessed with music and value great sound. Get a good pair of in-ears and use something like the Comply memory foam tips (several models and sizes can be had for different needs) and you will have a nice solution in a much smaller package. My current box is one third of the one for my Bose QC25’s, and then it also holds a Lightning to USB adapter and an external DAC / headphone amp.
Two main reasons I stopped using my Bose set
- bulky to carry
- less comfortable than in-ears (personal preference)
- strongly prefer the sound signature of my AKG N40’s