can't upgrade macOS version on Macbook air 2015 from Catalina to any newer version

I have a MacBook Air 2015 and I'd updated it to Catalina when it released. now I'm trying to upgrade it to macOS 12. but when I go to software update it says there's no update. and when I use link to App Store from any newer version than 10.5 after I click get it says update not found on software update window which opens