cvc-complex-type.2.4.a: Invalid content was found starting with element ‘base-extension’. One of ‘{layoutlib}’ is expected

Upgrade your com.android.tools.build:gradle in your build.gradle file to the latest version

e.g.

classpath 'com.android.tools.build:gradle:7.0.4'

And upgrade your gradle-wrapper.properties to the latest version i.e.

#Tue Apr 12 23:39:17 AEST 2022
distributionBase=GRADLE_USER_HOME
distributionUrl=https\://services.gradle.org/distributions/gradle-7.6-bin.zip
distributionPath=wrapper/dists
zipStorePath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME

Optionally, you can upgrade it using Project-Structure UI