ITead’s naming schema is a bit confusing but please understand that you can not flash a Silicon Labs based adapter like the “ZBDongle-E” (“Sonoff Zigbee 3.0 USB Dongle Plus V2”) with flashing software made for Texas Instruments based adpters like the “ZBDongle-P” (“Sonoff Zigbee 3.0 USB Dongle Plus” that is not the “V2” varient).
Note that you either need to stop Home Assistant to flash it or better yet unplug the USB dongle and plug it into another computer instead where you install the drivers and the flashing tool to flash it from there. You will of course also need to install WCH CH9102 device drivers to access the USB adapter.
If you have the “ZBDongle-E” (“Sonoff Zigbee 3.0 USB Dongle Plus V2”) then highly recommend that you use the Elelabs Firmware Update Utility → https://github.com/Elelabs/elelabs-zigbee-ezsp-utility (or walthowd’s updater image which uses it → https://github.com/walthowd/husbzb-firmware ).
Yes those are Python-based tools but you do not need to know how to read/script Python code to use them as all you need to do is install Python for Windows or Python for Mac/MacOS and copy the commands from their README.md documentation into the command prompt / command line tool.