You can check out Audioscience review for objective measurements on most of the current DACs. Here's a table of comparisons:
IBasso DC-02 is in the orange zone of the above table.
The Hidizs S8 is actually the same internally as the Tempotec Sonata HD Pro, which is rated very high in the blue zone, just that the Sonata HD Pro is an OEM version of it at half the price. Audioscience review is quite impressed by it:
https://www.audiosciencereview.com/...dizs-s8-usb-c-headphone-adapter-review.10823/
Though at the end of the day, measurements as above may not correlate with what we're able to hear.
I wrote a small review here:
https://www.head-fi.org/showcase/tempotec-sonata-hd-pro.24181/reviews#item-review-23794
I'm very happy with the Sonata HD Pro, it can hit almost the same standard of sound as my desktop rig, though at only $40 USD! But it can't drive higher powered gear like high impedance cans, but for most IEMs it is very good.
Good luck in your search friend! Hope the others can advise too!