I think maybe another way to say the same thing may be “get a DAC which connects to your phone via USB”.
Could be a dragonfly or a Fiio KA3 dongle, or a desktop DAC that has a USB. Many dongles will come with an OTG cable. Maybe you have one you want to use already that has a USB input.
But if they don’t come with one, you’ll need to get a USB OTG cable that has either lightning (for iPhones) or USB C (for Samsung etc) on one end, and USB A or USB C on the other end depending on what your DAC has. Most are still USB A, but we are beginning to see more and more USB C input ones. If you post the actual model of phone and DAC, and what geography you are in, we can probably help you find the right cable.
Also, it’s with saying that if you’re using your phone over a period of time you’ll need to keep it powered. On iPhone you use the camera cable to put power in at same time as OTG connects to DAC. I think with USB C you may use a hub.
This thread has a lot of inspiration: