The bow Lars Anderson is using in that video is a low tension bow. It would have nil effect on a hoplite or heavy infantry.
Archers helped break the lines in a formation, much liek closed ranged pelstats. They were only effective within 30m of the bowman and had a minimum range of the length of the arrow, around 1.5m. Until the arrow is fully released it hasn't reach top velocity so an arms length + arrow length past the bow string.
Also cavalry usually wore lighter armor than heavy infantry. They relied on speed to reach the archers which were usually placed initially infront of the phalanx or formation then retreated to the sides. In some cases they may have been used on higher ground behind the formation.
The English vs French Battles usually were successful for the English due to essentially hiding in woods on steep hills. They had a scattered formation behind and even high in trees. The French wore light armor compared to heavy infantry and were vulnerable due to a lack of speed. I believe many victories were attributed to muddy slopes that forced the horses to fall and dismounted their riders.
Alexander's cavalry on open field was able to counter mounted and infantry archers reasonably well. But they wore solid plate armor with hardened leather lining, which was better vs arrows than the chain mail used in medieval fights.
It would take a significant draw on a bow to penetrate ancient armor. Doing this at full stretch of a high tension bow a bowman could easily penetrate armor, but was slow at firing. Add to the arsenal of the infantry a nice Hoplon or shield and arrows would just stick or bounce from the shields. So even though in theory it was possible to penetrate armor, the actual occurrence was rare. There are many stories of medieval kings or generals rallying their troops by charging alone into the enemy. None died by arrow.
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