Thanks for the help everyone. Here are my thoughts on what I should do. While I really like the Pono > Cardas EM5813 in balanced mode, it is spooky holographic and immersive, very natural sounding; but there are plenty of times when it is just too boomy, and that is even with a not great seal. I don’t have a ton of experience, but it feels in my gut the Pono doesn’t play very well with IEMs. Plus there is the battery life thing. Anyway I do love that very mid-range centric natural and darker Pono sound (certainly some would note the rolled-off treble, but its very analog feel works for me); and having had the ER4s before, and the Hf5 now with a phone>dragonfly, I think I might try to shoot for a more fun, less analytical, don’t overthink it sound.
I am going to pair one of these with the Fiio x5ii, and it seems if I want a bit more of the target sound I noted above, I should head to the XR; unless I am not correctly reading what people are saying about these two new offerings.