You are using the latest version of the 3.2 but if you do want to use a Big Sur compatible version you need to use 3.5.
Audirvana 3.2 for Mac has been replaced by Audirvana 3.5 for Mac.
You can get Audirvana 3.5 that brings the strongly improved user interface, and further improved sound quality.
To get your upgrade, you need to enter your order reference on https://audirvana.com/buy/#offers
Here is your order reference of Audirvana 3.2: 90767627
Before installing Audirvana 3.5 you must uninstall Audirvana 3.2