System, vendor and boot gets replaced during a rom install. Data and internal storage should be ok, as you wiped/formatted it already. So its nothing special left from your TWRP restore.
All the device unique stuff (like the serial no, mac address, etc) stored in boot1 area should be ok, a data loss is really rare, but who knows. You can do a quick check if you like with TWRP, mount system and then run the 'idme print' command in adb shell. In the printout should be the serial of the stick, BT and Wifi mac_addr, board_id, bootcount, the header of KB and DKB partition and so on. If you do this, don't post your unique data here.
Edit: Have you tried the sideload option described in the posting here?
Hello! I was trying to clone one Fire TV Stick 4K to another. I've backup with TWRP from one FireTV Stick 4K next partitions: System, System Image, Vendor, Vendor Image, Data, Boot. Then was trying to restore all of them on another stick with...
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