Add .dropboxignore directory to exclude folders without using selective sync

I am unable to restore a folder I accidentially deleted because it's too large. It's too large because Dropbox synced the entire node_modules folder. I now have to revert two events with no clue as to which (if either) is going to bring back the actual files I need because I can't read through the incredibly designed infinte scroll with no search Event. I have been a paying member of Dropbox for over a decade and this still is an issue I cannot solve.