HELP PLEASE my Xiaomi BS3 is stuck in fastboot mode.

HELP PLEASE my Xiaomi BS3 is stuck in fastboot mode.

Hi. This is urgent since this phone is my personal one and I'm stuck here, its completely dead. I've read almost every thread in this section and tried the commands, and use the files they had but they do not work... anyways, here's the situation:

Last update ( KLEN2203050OS00MR1 ) hardbricked my phone. It was literally dead, I had no firmware, or ROM whatsoever. I already took it to a verified Xiaomi store and they gave it back to me (they didn't do much tbh just fixed the bootloop). I flashed with with EDL mode and now bootloader is unlocked and I can access recovery mode. When I try to flash, I keep getting the same error with the next files: system, vendor, product, and odm -they are .img files. And to add, I have another error saying " FAILED (remote: 'Partition not found') ". I've read multiple posts and threads that they were able to fix that issue with " fastboot flash fastboot " or something like that. I tried the command again days ago and tried to flash again, but no luck. I am trying to install a stock ROM. My phone is a Xiaomi Black Shark 3 Qualcomm Snapdragon 865. I believe I have the global version.

I would really appreciate any help really, since I've been dealing with this for 2 weeks now, and taking my phone to the verified store to fix it will take weeks and it's very expensive...