What was the source of the signal? Unless you know what the input signal value is, there is no way to know if -24dB is bad. How long the cable is. What frequency light is being used. What is being used to measure the signal. Is the meter recently calibrated, etc...
BUT with all those unknowns, I would say that =24dB sounds low. Usually you want closer to -10dB
If you want a reliable and long-lasting fiber optic cable for your household, then you can’t go wrong with buying AmazonBasics. Built with attention to detail, the manufacturers assure you won’t have any difficulty with this cord.
If this was any other site recommendation I would say it was a spam post since this is a thread over a year old.
Posts like this amuse me because of you have people post with such conviction that have absolutely no clue what they are talking about. Amazon basic only sell fiber cables used for audio connections it is not even close to similar to what is used for fiber to the home internet connections. The question also has nothing to do with what cable to buy since the fiber to ONT is owned by the ISP and you can not replace it.