We are propping up the AI with workarounds.

Therefore, I ask everyone who isn't too lazy to share their gaming experience (or purely analytical reasoning) on how to replace or enhance the AI on a map with many scripts,
without directly affecting the AI (i.e., without setting priorities or similar, as the authors of Single-player scenarios do, which my map is not).

It seemed to me that a relatively good tactic would be to give the AI heroes increased experience from the start (and maybe a few extra troops as well). Although I don't play much myself and haven't tested it extensively, the idea is that it should increase the speed of development and aggressiveness.
It might also be good to use MakeHeroReturnToTavernAfterDeath, or something like that. So that after losing the main hero, the AI doesn't become an easy target, but remains some kind of threat. Although this function can be a bit annoying if it happens several times.

For the price of 50 resource units, get 5000 experience or 10000 gold? -> The average level of all heroes on the map is calculated; if the AI is behind, it gets experience; if the AI is not behind and does not have a leading amount of gold, it gets gold.

I think all of this is going in the wrong direction, as it's an obvious overcomplication. It's easier to create a trigger for a new day and gradually add to the AI's resources – the same experience, if it's needed. And gold, as I understand it, is completely useless to the AI – in the fifth game, the AI is a cheater and buys units/builds buildings almost for free.
That is, I'm saying that for a human opponent, there is no difference whether the AI actually levels up on quests or simply has a head start.