I often have two windows open side by side and drag a link from one to the other, dropping the link anywhere on the page (this is often preferable to opening/navigating multiple tabs because it requires fewer clicks).
I was disappointed at first to discover that Brave does not support this basic functionality. However, while getting familiar with Brave, out of habit I happened to drag a link onto another window, and it worked! From what I can tell, the only difference between this window and other windows is that the downloads bar at the bottom is visible.
If I open a new tab in the window with the downloads bar, drag & drop works in the first tab, but not subsequent tabs.
If I close the downloads bar, drag and drop continues to work in the first tab, but not the second tab.
If I close the first tab, drag & drop no longer works in the remaining tab.
If I go to Window > Downloads and it opens a tab with my list of downloads, I can drag & drop links onto that page.
Glad I figured out a quirky workaround for my drag & drop needs, but please make link drag & drop onto any tab or window standard functionality in the browser.