Then just report it in the bug thread. Keep in mind, the developers don't own all the supported models, so they often cannot test the fixes that they try to provide.
It seems to be a modem issue, but you have forced the install of global ROM on a CN device, so you won't be able to flash the modem.
If you have a way to reinstall the CN ROM, it may be a solution. But this is not what you wanted in the first place.
You are not guaranteed to get an answer if it is your question. Also, keep in mind, it is a custom ROM forum, so you may not get answers on very specific questions about the official EU ROM.
My understanding is that you cannot unlock China devices currently
https://xiaomi.eu/community/threads/known-unofficial-unlock-xiaomi14-and-k70-series-bootloader-methods.70843/post-744411
@Xander00 For newer ROMs, you would need an account based in China to unlock a Chinese device.
As far as I understand, even non official services cannot unlock Chinese devices currently.