THIS STILL HAPPENS: You've downloaded the right version of Chromium, but it refuses to unzip without a corruption notice. We don't know what the devs are using to Zip the file, but it's NOT standard. Apple's Archive Utility can't handle it. Therefore, you have to use a compatible UNzip app. The only one I know of that works is Unarchive, part of Parallel Tools. If you discover another, please post! - - Shame on the devs.
Still too much Google snooping in Chromium. You're better off getting Ungoogled Chromium instead. It requires a plugin to use the Google Chrome App Store, but well worth it if you value your privacy and sanity.
For anyone still on a pre10.15 MacOS (10.7 to 10.14): after a few years using Brave, I've switched to Chromium-legacy by blueboxd, works perfectly. Use the builds numbered like 119.0.6045.105.1 (tagged "stable"), not the ones like 1211971 (Canary builds). I haven't met any issue in two months use.