Astell & Kern DAPs tend to have really good synergy with JH audio IEMs. Here i'm using my SP1000m with my Angie II. Admittedly an SP1000m is overkill for the Angies, as it cannot extract the maximum SQ out of the SP1000m. That is where my 64 Audio A18t CIEM comes in.
A few years ago (more like 4 by this point), Astell & Kern even colaborated with JH audio to tune their DAPs specically for those IEMs. The result is almost perfect synergy with the Angies. This probably applies to more modern and lower end Astell & Kern DAPs as well. A&K DAPs tend to be a bit limited in terms of what can be installed onto them, they run a modified version of Android, with an app whitelist. They are very fast and build really well. They sure are expensive but well worth it IMO.
If you are looking for something a bit more reasonably priced, take a look at the high end offerings from FiiO. Their old X7 mk2 paired really well with the Angies, I've used that combination for years on end before finally get the SP1000m.
My reason for upgrading was getting the 64 Audio A18t, but extracting maximum SQ out of the Angies was a nice side effect.
Hope this helps.