Disable MIUI System Ads (MSA)
Disabling the MSA solves the ad problem.
Open Settings app on your Xiaomi smartphones
Head to Passwords & security and tap on Authorisation and revocation
Look for MSA and disable it
Disable GetApps as well
GetApps is the official app store for Xiaomi smartphones. This app keeps on pushing ads and app recommendations.
Under Authorisation and revocation settings, look for GetApps and disable it.
Turn off personal ad recommendations
Turn off ads in Mi Browser
Turn off ads in Downloads
Turn off ads in File manager