Dear @RVB
if you want to get rid of BREED and if you want to get back to the stock bootloader, then just flash the stock bootloader via BREED.
In the following Chinese forum you can download the stock bootloader:
https://www.right.com.cn/forum/forum.php?mod=viewthread&tid=4064323&extra=page%3D3%26filter%3Dtypeid%26typeid%3D43
Direct link to the stock bootloader of the Xiaomi MI AC2100 (Black cylinder):
You don't need to know Chinese for this. Just click on the left orange button.
And you will be guided to the download.
Afterwards flash the file in BREED.
If God wills you will be then able to make use of the MiWiFi-Repair-Tool again.
For the ones, who have the REDMI AC2100 (white router with 6 visible antennas):
The stock bootloader can be downloaded here: