The update to the Google Play Store (via the Google News Telegram group) seems to be rolling out to some people now and supports dynamic colors. It’s apparently a server-side switch and may take a while to roll out to everyone, so the version of your Play Store app won’t make a difference. You can definitely make it more likely for you to get the update by making sure you are on the latest version of the app, but that’s all you can do. I do not have the update on my Google Pixel 5 running the latest Android 12 beta.
For the uninitiated, Material You’s dynamic color feature makes use of monet, a new theme engine introduced in Android 12 – and currently exclusive to Pixel phones – to extract colors from your wallpaper and generate a rich palette of pastel colors. Apps can then apply these colors to their user interfaces in different ways, which is what apps that contain material you typically do. Dynamic color support is one of the most exciting things that comes from Material You, as it makes each app’s design feel more personal. It also maintains consistency across apps and makes your smartphone experience feel more cohesive.
If you do not have the update yet, do not worry, you will probably get it soon.
Source: XDA Adam Conway