https://www.apkmirror.com/apk/google-inc/google-chrome/google-chrome-90-0-4430-210-release/
Look up "Chrome version 81". Filter the results to match your specific device processor architecture (usually ARM or ARM64).
: Compresses web pages through Google servers before downloading them, saving mobile data and speeding up loading times on older hardware.
is arguably better than Chrome 90 for Android 5.1.1 because it is under 1MB, uses the same WebView engine, and is still updated weekly.