Hello @Siana
if after you erased those bookmarks you did not reopened brave again (if you simple closed it without opened it then it’s fine)
go to your user based on your platform
then go to BraveSoftware → Brave-Browser → Default (if you have only one profile which i assume then this is your profile folder)
you will find 2 files
Bookmarks rename this one to anything you like maybe add 1 at it’s end
Bookmarks.bak rename it to be like the old name of the above file so it be Bookmarks
then open brave and you will find your old bookmarks
notice if you added any new bookmarks after delete then those new one will not be there but they are on the old Bookmarks that you renamed
if you opened brave after delete those bookmark both files will be the same
another way but it harder that you install app that restore deleted files and scan the drive where you installed brave on and hope they bring you the old files
by the way those files can be opened with any text editor
hope that help and have a nice day 