This sounds to me like the “Current Folder” feature.
Right-click a folder in the Outliner, and choose Make Current Folder. (The folder turns green, and the tooltip says it’s now the current folder.) When you drag an asset from the Content Browser into the Viewport, the new actor gets created under the current folder.
When you’re done, right-click the folder again, and choose Clear Current Folder.
(Note that it doesn’t work for Alt-drag duplicating or copy-pasting. Those operations use the same folder as the source actor.)