Download MIUI V220.127.116.11 China Stable Fastboot ROM for Xiaomi Redmi K30 5G from here.
Archive name: picasso_images_V18.104.22.168.QGICNXM_20200728.0000.00_10.0_cn_36ddc16bb9.tgz
Xiaomi Device name code: picasso
Archive size: 3.9 GB
Android version: 10.0
Optimized system performance
Improved system security and stability
Caution Please do not update firmware unless you know what you are doing, you really want it or it is absolutely necessary. Firmware updates may occasionally have bad results, like bricking your device, temporarily or permanently. The firmware update process is done entirely at your own risk. Before attempting to update the firmware, back up your data. BTW, a link doesn’t last forever.