So upgrade to macOS Sequoia, running Premium Business Security and now get an error in the console saying “obsolete OS” with a link to this page https://businesshelp.avast.com/Content/Products/SysReqs/SysReqs_Full.htm which only mentions requiring OS X 10.11 (El Capitan) and higher - preferably macOS 11.x (Big Sur) or higher, with at least 500MB of free disk space
Any idea when macOS Sequoia is going to be supported, it’s had beta versions available for some time for testing, avast should have been compatible from release date