Where can I find a macOSX Big Sur operating system download?

click on macOS Big Sur

please use safari. other browsers usually don't work.

then, yes, that mac is compatible. you may want to read this informative user tip: How to upgrade to Big Sur - User Tips

you can also try and boot into safe mode and download and apply the upgrade while in safe mode. How to use safe mode on your Mac - Apple Support

if neither of the above helps, you should start a New Thread to get the attention that your question needs.

i would think that if you are getting the "unavailable" message while using that link, as well as when searching the app store, it tells me that your mac is not compatible with big sur. what exact year and model mac are you trying to upgrade?

you're welcome. i'm always happy to help. :)

and sorry for the late reply. i felt like sleeping in this morning.

Tried to download Big Sur from your link, and I get a message that it isn't available. Searching for it in the App Store yields no results. What am I doing wrong?

2017 MacBook Air, currently running Mojave 10.14.6