Google no longer provides security patches for Chrome 71. This means any known vulnerabilities discovered after December 2018 are exploitable.
Modern websites are JavaScript-heavy. Chrome 71 will struggle with complex web apps (Google Docs, YouTube Studio, Facebook), leading to slow rendering, high CPU usage, and battery drain. google chrome ios 9.3.5 download
Log into your Apple ID on that newer device and "buy" (download) Google Chrome. Once the download begins, you can cancel it. Now that Chrome is linked to your account, return to your iOS 9.3.5 device, and it will appear in your Purchased list, allowing you to download the older, compatible version. Why Use Chrome on an Older iPad or iPhone? Google no longer provides security patches for Chrome 71
If Chrome was downloaded in the past, you can attempt to download the "last compatible version" via the tab in the App Store. Chrome 71 will struggle with complex web apps