Incompatible Google Chrome version on macOS 10.15.7
You have macOS 10.15.7. The application requires macOS 11.0 or later.
[Re-Titled by Moderator]
iMac 27″, macOS 10.15
Question marked as
You cannot run the current version of Google Chrome on Catalina – and as far as I know, Google does not make old versions of Chrome that would run on Catalina available for download.
Whether and far you can upgrade macOS depends on the hardware model, and hardware model year, of your Mac. You have not told us which 27" iMac you have. If it is from Late 2014 or later, you can upgrade beyond Catalina; tell us the specific model (e.g., "iMac (Retina 5K, 27-inch, Mid 2015)") and we can tell you how far you can upgrade.
How to download and install macOS - Apple Support
If you cannot upgrade past Catalina, you could consider other browsers, like Firefox – whose current version can run on Catalina.