So....I have not gone through this level of things on the DX320. It's been since Android 9, maybe 10 that I was loading custom roms on HTC and One+ devices. Everything I did was through adb commands (on MacOS) and recovery bootloader.
However...if you are seeing the recovery screen, your 320 is not totally 'bricked'. The recovery bootloader is working, it just needs the OS (custom firmware from iBasso). Someone smarter will correct me if I'm remembering wrong.
What happens if you put the image file that Paul had you download, onto the root directory of the sd card, then choose the 'apply update from sd card' menu item?
You are so close I believe.....