>> org-hide-drawer-all
>>
>
> I don't seem to have that command.  I'm using Org mode
> release_9.6.10-835-gf3de4c.

It was made into a command in
https://git.savannah.gnu.org/cgit/emacs/org-mode.git/commit/?id=13353f1fa34f6f085ffbf142b380af7308f02981

I see, I found the command, it's called org-fold-hide-drawer-all (not org-hide-drawer-all).

However, strangely, it doesn't close drawers that have been opened by the bug that causes drawers to remain open after the searching (eg, those opened by searching for "text" in the file I included in my bug report).