Yes, you will need to flash the appropriate firmware for it to act as a router https://www.youtube.com/watch?v=4usy1ESI4k4
There are 2 versions of the dongle - P and E. The E version was only recently released but the P version is well supported. The only issue is that you probably need to use a cable to plug it into the battery pack as it's going to be quite unwieldy when plugged in directly.
The one I linked to has been discussed to death on this thread DIY- Battery Backup Hubitat- under TEN bucks-NO soldering. And yes my Tuyas still work fine if you disconnect power due to the way these are designed and the repeaters don't draw enough current to pose an issue, with the only exception being if the power outage is long enough to completely deplete the battery then when power comes on there may not be enough to charge and power the device simultaneously. That said these repeaters draw so little power that in my area this does not pose an issue.
