The amount of effort needed to craft your legendary armor in World of Warcraft: Shadowlands justifies wearing it as much as possible. You’ll need to get familiar with dungeons, raids, Torghast, and World Quests if you’re going to sport these incredible pieces of equipment. If you want to wear more than one, you’re out of luck for now, but this shouldn’t be permanent.
Right now, you are limited to wearing one piece of legendary armor for each character in Shadowlands. In all likelihood, this is temporary, as Blizzard is still rolling out new features where components for legendary armor could appear. We still have more dungeons to look forward to, as well as other wings of the Castle Nathria raid, and any other new content planned for the still-new Shadowlands expansion.
Even though you can only wear one piece of legendary armor, don’t let this stop you from working at it. You can get familiar with Torghast and the Twisting Corridors; in fact, the Twisting Corridors is a great way to find the specific legendary piece you might need. When you put together one piece of legendary armor, don’t forget to upgrade it; you can raise it to a maximum level of 4, but you’ll need to find material all over again. Don’t say you have nothing to do in Shadowlands.