Actually, they knew math so well that they knew 360 would work in most cases and was easier to work with than say 365.2425 or something. The Bible indicates that God sets the irrational numbers precisely so that different similarities would be close enough to work with but still imperfect.

For instance, Book of Enoch points out that 360 is prevailing but 364 is closer and has more advantages and still can be worked with in the same general way.

Absolutely 72 was used as a round number due to these synchronies; which is why 360 or 2.5 gross was also used as a round number. It's probable that after generations the approximation 72*360=25920 would've been guessed (actual currently 25771.57534, which varies based on measurement specs and adjustment over time). The Bible also says Solomon built the temple laver just fine even though he used 3 as an approximation for pi.

You are right that many of these supposed connections are excrement. But often by reverting to your correct perspective about round numbers the actual math of the day can be recovered and the original claim somewhat vindicated even though it's expressed in different terms. This week I learned that Euclid discovered a working version of the law of cosines without ever inventing a cosine.