There are some issues that you will face using built-in applications. We'll talk about these first, and then we'll talk about applications that you download later from the App Store.

All DRM Content is unavailable in macOS Big Sur and newer. This includes things like DVD Player, Music Videos, Movies, DRM Content is Safari, etc. Good news, there are a few work-arounds for the DVD Player and DRM Content in Safari.

For the DVD Player, you can get a third-party application. I recommend Final Video Player: Final Video Player in the App Store

As for issues in Safari, I would recommend using a third party browser that doesn't require metal graphics to run. Firefox is an excellent example of this. Firefox Download