Mod does not edit Autoresolve. Problems you mentioned are base game.

Hmm I didnt notice AR was this bad in base game. An army of 15x Cathay Tier3/4 units beaten by 13x savage Orcs? I fought the battle and destroyed them. It sucks.

actually it feels like something happend to auto-resolve in 2.4
i was playing vanilla and was getting valiant defeat auto-resolves all the time, despite having superior forces

Auto resolve never made much sense. Sometimes it will give you a pyrrhic victory where you lose half your army, or a straight up valiant defeat, then you play the battle manually and you wipe the floor with your enemy with zero unit losses. And sometimes it will give you a close victory where you don't lose a single unit, then you decide to play it manually since you think you can do better and you struggle to figure out how to win without losing half your army, or even how to win in the first place. And it all comes down to a simple thing: you cannot accurately simulate all the variables and accurately decide the outcome with just mathematics.

It works like this in vanilla, it works like this with grimhammer. It worked like this in the first two games too. Nothing really changed as far as I can tell.

WH3 has completely made autoresolve extremely dependant on the Battle Difficulty setting. I like to play on Hard/Hard but many times I have a battle which should be easily won if I played it but don't want to waste my time. So I go to settings and change the battle difficulty to easy and then the autoresolve is much better. I put the difficulty back up afterwards. You can also do this trick so you don't have to fight every single battle especially on harder difficulties.

Interesting thanks guys. So even SFO's changing of all of the unit stats (even if it did not specifically change AR settings) would not affect AR vs the vanilla game?

it would, but not enough to change the strength on grand scale
everything you do affects AR except certain circumstances, where nothing you do affects it
its not very modular at all so we don't mess with it much

even this is a tl;dr answer, so even tl;dr of this, the the answer that is enough for most people is what Venris said

Sorry guys but autoresolve is COMPLETELY different. In vanilla campaign battle where you are stronger AR takes a roughly even amount of health from units on a regular basis whereas in SFO a similar battle completely destroys several units even when you are stronger and should clearly win. Units that have lower health are especially affected, and you can lose very elite units to low-tier enemies even when manually fighting the battle you would never lose anything.

I am not saying Venris has specifically tweaked AR, but the fact is that in SFO it behaves VERY different to vanilla, iikely due to all the stat changes you implemented that have affected the balance. This means you have to fight so many crappy battles manually to avoid losing important units and me and a friend have for the moment stopped playing SFO purely because of this issue, which makes me sad.

This is fully repeatable behaviour, so go start the same campaign in SFO and vanilla and you will see how different the autoresolve behaves.

It's always been really sketchy since WH3 release. There are times my minor garrisons fight like gods and beat a legit LL 20 stack and other times my stacks get wiped out when I can then win with <10% casualties. The amount of damage my wood elf garrisons inflict sometimes is far more than I could manage. It just doesn't account for some things very well and places too great a weight on others.

Watching my High Elf armies lose their Ellyrian light cavalry in EVERY auto-resolve battle is pretty frustrating. If I swap them out with something else like horse archers then no losses, but even against tiny armies they just die every time and force me to play the battle.

Also I find that using the Razor Standard on any army increases the likelihood of auto-resolve losses. I can look at a battle where I won't suffer losses and if I assign the banner then units will start auto-dying. It is baffling.