taxes 2023 on an Apple OS Big Sur

There probably is none since many third party developers only support the three most recent versions of macOS these days. Instead of using software, why not utilize the tax preparation website through a web browser? Even this will be limited soon since even the browser developers are now only supporting the three most recent versions of macOS. At some point those older browsers will no longer be able to access some web sites.

If you have a 2015+ Mac (there are some exceptions), then you can install an newer version of macOS which may be compatible with the tax software. You can see which versions of macOS various Apple hardware supports in this article:

https://eshop.macsales.com/guides/Mac_OS_X_Compatibility

If your Mac supports a more recent version of macOS, then you can access various macOS installers by using the information in this Apple article:

How to download and install macOS - Apple Support

TurboTax Online is compatible with Big Sur (and even 1 or 2 earlier versions).

I've used their online version for years and have found it to be very good. Never any installation issues since it is on online version.