If you have Xiaomi Global Version 14 use this fix.
Mobile sees the SIM but you have no signal?nal? Download this package: Android 14: houji_network_fix_A14 HyperOS 1.0 Android 15: houji_network_fix_A15 HyperOS 2.0 install in fastboot: 1. Unzip the ZIP file on the PC 2. Connect the mobile phone in fastboot mode to the PC 3. Run the installation...
xiaomi.eu
If you have a Chinese device, just install the xiaomi.eu ROM
The Chinese device does not support eSIM