If the YN560-TX won't even power up or exit update mode, there's not much you can do besides return it to wherever you bought it for exchange or refund. If that's not an option, then you've got to decide if putting it on a slow boat back to China for factory service is worth the effort/cost (which likely will cost more than you paid for it).

If the only flash you have is a YN685, you might consider getting a YN622C-TX (if you're a Canon shooter) instead.

The YN685 is basically a YN622 system flash that can also be set to receive instructions from the YN560/RF605/RF603 system, but it is limited to the lower capabilities of the manual only YN560 system. A YN622 controller would allow you to fully exploit the wireless capabilities of your YN685 flash.

The YN560-TX PRO adds the ability to use TTL and other advanced functionality with YN622 system flashes in slave mode if the YN622 system flash has the latest firmware installed.

Existing YN685 flashes older than mid-2019 probably need a firmware update to be used in TTL mode with the YN560-TX Pro. The biggest issue is that some YN685 copies have early firmware versions that are not updateable. Even if the firmware is a version that is updatable, you need a YN622-TX to do it wirelessly since the YN685 has no usb port. If your YN685 (Canon) is not already running firmware version 2.0.2 or later it can not be updated. I have a YN685 that is firmware version 1.0.2 and there is no way to update the firmware, even when I'm using the latest firmware version for the YN622C-TX and latest version of YN Flash updater.

Or you could switch to Godox/Flashpoint (Adorama's private nameplate for Godox products). They seem to be more reliable than Yongnuo, and the Flashpoint version is backed by U.S. based Adorama so if you're in the U.S. you don't have to send stuff to China to get it serviced. The Godox/Flashpoint 2.4Ghz radio system also uses the same protocol for everything from their most basic manual speedlites all the way to their top end studio monolights.