The problem is that history items are not tabbed / grouped. Unfortunately history does not contain a filter to group previously closed windows together.
Also history sorts websites in order of last visit descending, meaning that the pages that you did not visit a lot in those groups are now way at the back of your history, while more frequently visited pages of the same groups are at the top.
So it basically becomes a clusterf*** that can never be restored unless you spend an hour on sifting your history items from the past 2 weeks.
And because there is no option to select multiple tabs from history to open at once, it is even harder to restore your lost windows. See my request on adding check buttons in the history menu. So coming from Firefox, I must say that the history part of Brave could do with some improvements that are as basic as adding checkboxes and a filter to group tabs in ‘sessions.’