This site setting is unrelated – it only applies to posts deleted by the author, which will stick around as (deleted by author, will be removed in 24 hours unless flagged) for the specified time.
Profiles with deleted topics once showed a red “notification” to staff members, but it seems to be gone. Maybe this was dropped when the Activity page was restructured (by @sam if I recall correctly).
You can definitely use the Data Explorer to find deleted topics, though.
And here’s how:
Run this query:
SELECT *
FROM topics
WHERE deleted_at is not NULL
AND archetype = 'regular'
Look through the list to find the topic, and memorize the ID.
Then, visit /t/<id> in your Discourse install to view the topic. From there, you can easily restore the topic.