The Venetian military relied heavily on the Fanti da Mar/Schiavoni depending on the period in game but typically speaking the regiment was not only the first modern understanding of marine as amphibious infantry but also the first permanent standing army regiment in Europe since the ancient era. They also tended to make up around 40-60% of the total military force at the Venetians had at their disposal both at peace and wartime, not the pitiful handful of units the game mechanics allow for, they were also typically far better fighters than the janissary troops they most often faced, making the whole 10% shock damage taken a bit weird considering they were for the most part powerful shock troops armed with a arquebus/musket, 2 pistols, a basket hilt sword and a yagatan long knife.
I do know of Venetian history but thank you for elaboration nonetheless.
Heavy galley use in the Mediterranean wasn't about standing up to "heavies" They were just far more useful in the heavily coastal area thanks to the variable wind conditions. The idea that a galley is stronger than a heavy until 17th century is just kind of weird, especially considering that galleys were lightly built with a few guns running down the middle of the ship and only fired once or twice per engagement while the majority of the fighting was done in boarding action. The much lower hull form of the galley also made it quite vulnerable to the much higher built heavy style round ships. Not forgetting the original heavy warships of the era were originally designed by Genoa and Venice to enhance fleet abilities of their largely galley based navies. Large ships were then organised into composite navies and the galleys would help maneuver the heavier warships into the most favourable winds and positioning, enhacing their firepower. Galleys were also considerably useful in peacetime patrolling against pirates and corsairs which were common in the Mediterranean basin, it was far more the need to deal with these outlaw threats that elongated the lifespan of galley use than their wartime fighting abilities against what is obviously a superior fighting ship in the "heavy".
This is not true, while amphibious capacities of galleys were definitely their main advantage and a reason for their widespread use, another reason for using during age of gunpowder was because galley fleets (which were also more expensive to maintain) had superior capacity in naval warfare before mass produced iron cannons become available in early 17th century. Simply put, a galley fleet was able to bear more cannon towards a singular direction with much faster speed and agility. When you consider that roundships had 8 to 12 cannons in their broadside in 16th century, on much longer platform, several galleys next to each other had more firepower on their bows.
Also while galley's low frame is a disadvantage in boarding, it's actually an advantage when it comes to sinking roundships because they were able to shoot their cannons at more critical water level of roundships. Another point to consider is because galleys could shoot their cannons towards the direction they were moving towards, regardless of wind conditions, their formation was much more offensive while roundships are necessarily defensive because of their inability to chase and fire at the same time. Genoese and Venetians (and indeed Ottomans and Spanish) used "heavies", that is roundships, in Mediterranean but only as support vessels because of their cargo space and their ability to defend naval areas as floating fortresses. Roundships only started to surpass galleys in combat ability because a galley was limited in its cannon amount due to its inherent limitations in size because of being powered by oarsmen. While galleys could only carry up to 7 or 9 cannons on their bows roundships started to carry upwards of 30 cannons on their broadside thus surpassed galleys in combat ability. Galleys became obsolete because they couldn't become bigger without becoming too slow and too expensive in terms of manpower.
In short, galleys were the most effective ships in utilising the limited amount of cannons the states at the time could produce, they became obsolete when cannons could be mass produced thus naval warfare became more about having as many cannons on ships as possible. A good comparison on land to how galley warfare was fought in 16th century is line battles of 18th century, which became obsolete because of higher firepower of breachloaded rifles and machine guns.
If you do have an interest in the warfare of the area and capabilities of galleys, I thoroughly recommend Guilmartin's book "Gunpowder and galleys".