Android 5.1.1 may be a dinosaur, but it doesn’t have to be a brick. Using the verified (Chrome 90.0.4430.210) allows you to safely browse most of the modern web, albeit with security caveats.
Because the Play Store will try to update Chrome 90 to a newer, incompatible version (which will crash), you must disable auto-updates: google chrome for android 511 link
Google has never released a Chrome for Android version 511. The last three digits of Chrome builds are usually in the range of 001–999 per major version, but the major version number is what matters. Major Chrome releases are sequential: 120, 121, 122... 511 does not exist and likely represents a buffer overflow trick or simple fake versioning used by malware authors. Android 5
If you are looking for a general review of the current Chrome experience on Android, Manage Chrome safety and security - Android - Google Help The last three digits of Chrome builds are
In that case, the article can focus on Chrome for Android, explain its features, how to use it, latest versions, and maybe note that the version number mentioned might not be accurate, but still provide relevant information. The assistant should also mention common misconceptions about version numbering in software to help the user understand why they might have seen that number.
Several independent third-party developers still build lightweight Android browsers optimized specifically to run on older operating systems with minimal ram. Searching for an "Android Lollipop compatible browser" on secure app platforms may yield functional alternatives to Chrome.