UPDATE June 22
Beta 1 of macOS Ventura supports AVIF in the Finder and the built-in Preview application.
There is a limitation with Finder in that it does not yet associate *.avif files with Preview. You may open AVIF files with Preview, but you must manually select the "Preview" application. Otherwise, Finder will inform you it does not know which application can open the AVIF file.
So, AVIF is definitely on its way to macOS, but it has not yet appeared in Safari. Safari falls back to JPEG for AVIF tests. However, with AVIF working with Preview and Finder, it is safe to say that AVIF is on its way.
AVIF
As a contemporary image format, AVIF combines both efficient compression and functional flexibility. Compression can be lossless or lossy. Like other formats for storing image and graphic information, an alpha channel records information on transparent areas. Transparency data releases objects for use in user interfaces, collages, or company logos, for example. Furthermore, AVIF supports extended color spaces, as well as High Dynamic Range functions. In high-contrast images, HDR technology makes images bright and vibrant while enabling solid colors and contrasts. It is also possible to use animated sequences like those in GIFs. According to the current data, the AVIF format has a 50% reduction in image size compared to the established JPEG format.
macOS
Apple's macOS is a desktop operating system. As a desktop operating system, it is designed exclusively for Apple's laptops, iMacs, and MacPros. In 1984, it was first introduced for Macintosh computers, the basis for all Apple PCs since. macOS Monterey is the latest version of macOS. A new Safari browser, improvements to Facetime, and Shortcuts scripting language for automating tasks were all introduced in this update. Several recent versions of macOS integrate tightly with Apple's devices and services. iPhone users can accept phone calls on Macs by using the Messages app. At the same time, their Macs are equipped with the Siri phone app. iPads can be used as secondary screens on Macs with a feature called Sidecar. With the macOS operating system, people with disabilities can use their computers with ease. Tools like VoiceOver, Accessibility Keyboard and Text-to-Speech are a part of this.
macOS AVIF support
macOS doesn’t currently natively support AVIF images or sequences. When users transfer or download AVIF images, they won’t be able to open them to view. As of September 2021, Apple has no public plans to introduce AVIF support to the macOS operating system. However, there are some third-party tools to ‘patch-in’ AVIF support. For example, a plugin called AVIFQuickLook allows users to view AVIF files with the quick look command.