I tried to delete those numbered folders (first I moved them and then I deleted them) and brave kept working correctly, no problem.
Today update to the latest version of brave (Version 1.23.75 Chromium: 90.0.4430.93 (Official Build) (64 bits)) and check those folders and they occupy very little, just about 200kbytes, possibly it was solved. I will check every so often to be sure …