Is it true that zakat consumes hoarded wealth until it falls below the minimum threshold (nisab) if it is not invested, and is the hadith "Trade with your wealth before zakat consumes it" authentic?

It is a tangible fact that wealth decreases with zakat if it is not grown and invested. If someone possesses wealth exceeding the nisab and does not invest it, but pays its zakat every year, their wealth will diminish. There are hadiths—though their chains of narration have some discussion—that encourage trading with an orphan's wealth so that zakat does not consume it. Among these are: "Whoever is a guardian of an orphan, let him trade with his wealth and not leave it so that charity consumes it," and "Trade with the wealth of orphans so that zakat does not consume it."