Yes iem is the most important part but with the right Dap it can take the iem to the next level. I own 2 UM Maven II sets. It's my end game but even used it's over what you want to spend. Dx340 takes them to another level completely so was worth buying the 340 over keeping the Dx260. Actually just sold my spare Dx340 to a friend, yes I owned 2. Bought a used Dx180 to have as a spare. Sounds like you want an iem that has good bass. Used CFA Bonny with Effect Audio Ares S 1 or 2 which cleans up its muddy bass should be able to be had used cheap but not the most technical iem. My Fir Audio VxV would be good if you can find a set used. Only paid $300 and really sound good. 64 Audio Trio would be good - good bass and great technicalities. For $900 you could get a used UM Mest Mkiii - don't get the stock cable to save money. I am probably not the best person to answer your question as I have not owned as many iems as many here and those I have just about all have been +$1k. I for sure would buy used.
Bloom will be sending out a loaner Dx260 Mk2 as soon as they get their stock in. I will post some pictures when I get it. Have to burn it in for sound impressions. I do not think Ibasso changed the Amp or tuning so should sound like the Dx260 I used to own.
