From reading this thread, to me it sounds like the keyboard is "working" (it's showing up as a keyboard and the keys output appropriate scancodes to the host, da?), but that 1) it simply wasn't pre-loaded with VIA and/or Vial firmware (which would be why neither app detects your keyboard...you have to have VIA-compatible or Vial-compatible firmware running on it for either app to detect the 'board!), and 2) you're having trouble getting the keyboard's controller to either go into bootloader mode or at least to remain in bootloader mode. All in all, at least to me it sounds like either a software or usage problem, not defective hardware...that said, though, I've never used a split 'board like your Ergodash.
In looking through the QMK git repository, it appears that the Ergodash source files *used* to be located at the root of the /keyboards directory, but as of January 31 they've been relocated to /keyboards/omkbd/ergodash. So if you made a recent checkout of QMK-master from Github, and you couldn't find /keyboards/ergodash, that would be why. A simple 'find ~/qmk_firmware/keyboards -type d -name "*ergodash*"' against your local checkout should've revealed this ('man find' for details on how to properly use POSIX 'find' command).
I'm also not finding *ANY* evidence that any of the keymaps for the Ergodash that ship with the base QMK-master source tree contain VIA or Vial support. There is no 'vial.json' file in any of the /keyboards/omkbd/ergodash/rev1/keymaps subdirectories (not 100% how all keyboards do it, but "usually" there is a 'via' keymap for VIA-supported keyboards, and if it has additionally been ported to Vial, a 'vial.json' file in that same sub), and an addition, the Ergodash does not show up on the list of officially-supported keyboards on the VIA site (caniusevia.com). So even if you build your own copy of QMK from source and manage to flash it to your 'board, it's still not going to show up in either VIA or Vial, not at least unless you put in some work to add the VIA/Vial support to your copy of the QMK source tree first.
After doing some more searching, it appears that the designers of the Ergodash have made a build of a VIA-enabled firmware, and posted it for download here:
https://github.com/omkbd/ErgoDash/tree/master/Firmware -- note that this is just the firmware *binary*, and doesn't seem to contain whatever QMK source code modifications they might've made in order to achieve it. But presumably, if you flash this particular firmware to your 'board, it will work with VIA.
It might even be the case that, as-shipped to you, it's been pre-flashed with this VIA firmware. BUT note that the way that VIA works is that, even if your keyboard's controller is running VIA-enabled firmware, the VIA utility
still will not detect it if the version of the VIA utility that you are running hasn't itself been updated to support your particular keyboard. And from what I can tell not only from looking at the VIA site but even their own git repository, the Ergodash designers haven't yet even submitted a request to have support officially added to a future version of the VIA utility. You can still use it with VIA, though: what you have to do is sideload support for your keyboard into your copy of VIA by 1) downloading the firmware ZIP file from the Ergodash git respository that I linked to earlier, 2) extracting the ErgoDash.json file from that ZIP, 3) while in VIA, go to Design > Load Draft Definition > select the JSON file. THEN VIA will finally see your keyboard. (And you'll have to do this EVERY TIME YOU LAUNCH VIA.)
So the whole problem with your keyboard might simply be that even though it's already got the VIA firmware loaded on it, you simply weren't aware that you need to take this extra step to make VIA see it.
For keyboards that aren't specifically running Vial-enabled firmware, you can still control a keyboard running VIA firmware with Vial, but you have to do the equivalent to sideloading the VIA JSON into Vial as well (in Vial, go to File menu > Sideload VIA JSON > select your ErgoDash.json).
Only once VIA has released an updated version of their utility (for VIA use) or you yourself have built a Vial-enabled QMK firmware image (for Vial) can you avoid the extra step of sideloading the JSON definition file in order to use these GUIs to configure your keyboard.
