The New York Post is a tabloid, so I wouldn't put much stock in what they say.
The Post article is just repeating info from a Bloomberg article that reported on recent price drops, not future ones. I agree that the headline is misleading (headlines often are), but the article itself says “as much as“ 25% for SOME categories of diamonds.‘Are dropping’ is a forecasting of the future. That’s tricky. In 22 and 23 certain diamonds dropped by as much as 25%. That’s not the same thing but the news people are easy to confuse. Typical was closer to 5-10%. Will that happen again in ‘24? Maybe, but I wouldn’t be so certain. There are other pressures at work here and predicting the future is notoriously difficult. If you can buy cheaper, great, but I wouldn't lose a lot of sleep over timing it.
At the moment, lab diamonds hold virtually no resale value.
BTW, if you look at the Pricescope charts for diamond prices you see some upward trends in recent weeks.