As a garlic farmer it always saddens me that they don't bother to explain the physical structure of the garlic in these kinds of videos. All alliums have some form of the compounds allicin and allicinase but with garlic they are held in separate cells. So the reason the flavor gets stronger is because you are bursting more cells and mixing the two compounds in greater quantities. It's a lot like a glowstick. An onion, by comparison, the two compounds are inside the same cell. That's why the direction you cut an onion (with the grain or against it) determines how much of the two compounds mix. But because they are held in separate cells the reaction is more pronounced in garlic.
It takes 20-30-ish seconds for the reaction to take place so if you cut directly into heat you aren't giving it time to do it's thing. This is because heat breaks down the compounds, both pre-mix and post mix. Some garlic varieties can actually survive low temp roasting without losing flavor. But if you want the best flavor, add the garlic at the end of the cooking process, or if you want the mellow suffused flavor do it half and half.
There are some 150-200+ varieties of garlic that can be divided into groups in a number of ways, but basically there are three evolutionary lines that gourmands and growers divide into 11 or so subgroups. A curiosity of garlic is that no wild garlic exists so we don't know where it actually evolved. There are two genetic epicenters, one in south-central Asia and another in the Middle East. Each variety is adapted to a slightly different climate or is more tolerant of various climatic differences and due to this some varieties simply will not grow where the winters are not cold enough. By the same token, some of the warmer varieties (creoles and turbans) will not do well up North. But also due to this, there is a slight yearly variation in the flavor in even the same variety that is dictated by the climate, much like wine is affected by the growing conditions of the grapes. Some varieties are very spicy kind of like mustard, but others aren't spicy at at all. Some are mild and sweet with high sugar content and high solids, others are rank and stinky like garlic is supposed to be. Some store well, others, like the Asiatics, do not store well. But in the end, they are all garlic. There are some varieties that have a kind of wang to them, though. But the harvest time dictates whether or not the flavor is more pronounced or the storage qualities are improved, as it's a trade off. You can't have both (though the storage qualities can be adequate, you don't have to store it for two years honestly, though silverskins can last that long).
However, the part that always frustrates me the most, is because culinary artists prefer larger bulbs those are the ones that people seem to want. It's pure laziness as the smaller cloves have more flavor packed into them. As the clove grows in size the flavor is diluted, it's a non-linear relationship. So bigger is not better, it's actually milder with a higher solids content. But the garlic you buy at the store is either mass produced in California or imported from some other country and neither compares to anything a small-medium craft garlic farmer will produce. The strength of the flavor is 10-30 times stronger than the stuff you get at the store, so while it takes longer to peel the tiny cloves, you actually don't need as much of it. It's real easy to overpower traditional recipes with gourmet garlic.
This is the best book on the subject: Amazon wants $20 more than this garlic farm charges for it.
https://filareefarm.com/the-complete-book-of-garlic-a-guide-for-gardeners/