No, the linked Adobe web page is quite old. It’s an introduction to Adobe RGB (1998) back when that was new, and seems to date from the mid-2000s based on the versions of Adobe software mentioned in the article. The PDF linked on that page is dated May 2005. The other download is the Adobe RGB (1998) color profile, but today, every Mac already has that built in as part of the default macOS profile set, so it should already appear in Mac profile menus even if you have no Adobe software installed. You’ll find the Adobe RGB (1998) profile at /System/Library/ColorSync/Profiles, which is an OS-restricted folder that users and applications can’t alter.
Now, that’s a separate question from whether a display is capable of Adobe RGB. The BenQ 271c claims to cover 99% of Adobe RGB, while the Apple Studio Display covers Display P3 which is similar in size, but covers different colors which can be good or bad depending on which colors are important in your work. (There have been some discussions about that on this forum.)
Lightroom Classic is going to edit in ProPhoto RGB regardless of what display you use, and Photoshop works in whatever a document’s color space is (Adobe RGB, etc. Each display can show you the colors that are in common between its gamut and the gamut of the working space.
The Studio Display is capable of wide gamut P3 and probably defaults to it. But If it works like the P3 display on my MacBook Pro, the Studio Display might not have an Adobe RGB Reference Mode or a way to create one. That would be understandable since it does not promise to cover most of Adobe RGB.
The answer to both questions has a lot to do with the colors you typically have in your photos. If you use a lot of colors near the edges of Adobe RGB that P3 doesn't cover, that might tilt you toward the BenQ. But if the typical colors in your work are mostly within the large area that Adobe RGB and P3 have in common, or your colors typically extend into P3, then the Studio Display would still be good.