Thanks to Berserker, installing such a mod is not difficult – Era2 is installed on the SoD (which does not affect the original game), and the mod is added to it; the mod is launched through Era. This mod can also be completely customized to suit your needs.
Among the additional features of Era, one can note the calculation of the number of creatures that can be killed when assessing damage, a rather adequate reaction of the AI to the innovations, custom buttons, fixing various bugs, and much more.
Regarding build orders, you need to think very carefully, and especially about 3-4, it is unlikely that such diversity will be possible; at most, I think it is 3. Unless, of course, some other restrictions are introduced, for example, no more than 3 buildings can be built in a city per week; then, even if there is a branching, for example, from elves, you can build lumber mills or pegasus stables, the player will have to make a choice based on the intended goals for the current week.
Regarding water, I have long had a suggestion to make the sailing distance 1.5-2 times longer than it is now, because it is strange that ships sail slower on the sea than an army crawling on land; in Heroes 1500, a ship has a speed of 1500 per day, and speed 4 has 1560, i.e., even the slowest units in the army can travel further than the sea wind, not even mentioning landing/unloading. I would generally suggest making landing/unloading dependent on the size of the army, and the exchange of the hero with the ship should also be taken into account.