There is no direct path to this main hub area other than fast traveling. That being said, when new players get there, they may not immediately know how to leave. However, it’s a fairly simple process. To leave Roundtable Hold in Elden Ring, use the map…
Fast Travel In, Fast Travel Out
Since there’s no direct pathway from any land in the game to the Roundtable Hold, the only way to get out of it is the same way as you entered it. From anywhere in the Roundtable Hold, simply open your map and fast-travel to any Site of Grace that you’ve already activated.
You can also approach the actual roundtable at the center of this hub area and interact with it. The bright light hovering above the table is actually a Site of Grace. It functions just like all the other Sites of Grace in the game, which means you can also open the map from here to leave Roundtable Hold in Elden Ring. You can also use this to level up, equip magic, and store items.