AnotherGame is a mod for ToE 3.1.

Yes. There's still a second town to reach. Why are you ignoring the gameplay on the map itself?

Based on experience with Heroes 3 maps, new towns are usually captured within the first week (I haven't played on Heroes 5 maps for a long time).
I understand that Heroes 5 maps are more complex, longer, and less playable (in my opinion), but not to that extent. Or are you spending months on IRMG without capturing a second town?

Is a long battle a bad thing? Sorry, but I want to be sarcastic, but that would be off-topic :)

A long battle in clearing a dungeon, when a player deliberately prolongs the battle to resurrect themselves repeatedly, is not just bad, but disgustingly bad, in my opinion. Minimum tactics, maximum time waste. I would reduce the number of healers to 5, restoring the standard initiative. This is definitely enough for the vast majority of battles (without deliberate prolongation), from start to finish.