If you enter the command "adb devices", the device must be started and USB debugging must be enabled.
If you enter the command "fastboot devices", the device must be in fastboot mode.
You cannot install xiaomi.eu custom ROM using Miflash.
If installing ROM using Miflash works, it means you don't have a problem with fastboot drivers.
So installing xiaomi.eu ROM using fastboot method should also work for you...
Seriously?
Different android, different OS and lots of other variables.
https://xiaomi.eu/community/threads/hyperos-2-0-stable-release.74372/post-747479
If you don't understand the issue of custom ROM and are not interested in searching for information, it would probably make more sense for you to return to stock ROM. ;)
In that case, I can't help you any more. You will probably have to use the services of someone who will try to install the ROM via EDL (service or online services that have an authorized Xiaomi account).
If you can get into fastboot, install the xiaomi.eu ROM. ROM for Xiaomi 14 (houji): xiaomi.eu_HOUJI_OS2.0.112.0.VNCCNXM_15.zip
Use fastboot installation. https://xiaomi.eu/community/threads/how-to-install-xiaomi-eu-rom-for-devices-a-b.62738/post-624043
Your data will be deleted.
1, are you using a custom ROM from xiaomi.eu?
2, do you have a Global version of the device?
3, If you installed the current xiaomi.eu ROM, the network (modem) patch is not used