How to hold AI Yuan shao with blobbing ?

Introduction

Yuan Shao AI benefit from all the value and knowledge at the start (AI checking values) and more you are a threat toward a faction more easily he get friends.

The easy way : Kill Yuan Shao

1) Proxy war him as Cao Cao and try to get NAP with him (filthy mastermind)
Get some coalition deal (hostile to yuan shao, not at war and also his neighbours) meanwhile with his neighbours just pay as you can with the quick deal menu.
Easy money like that by the way you start the war and get some cash in agreement if you are his "NAP friend"
The standard DLC way :

2. Start as Huang Shao (Yellow turban) and attack him while rushing north east toward the peninsula to get a map corner advantage and push then north east in order to deny vassal.

The hard way :

3. Be in a coalition with Yuan Shao send spy pray that you can sabotage him.
   Reject all his call to arms against cash but when you are at war just call him what ever thing happen in order to keep his relation low with others and making him breaking deals if you can. Just conquer faster than he can make vassal (coalition with liu bei or whatever 3 province guy if you can and subside their war) to do that make a doomstack rush toward south like sun jian free real estate here you can't fail that occupy as much land as you can for the final showdown.
   

When you get a blue general (commander brain type) as army stack his cunning and long range unit use it as garrison for walled city. It increase the amount of ammo and make your army potentially more lethal.
The gray one (thief build) max his sword retinue he give better armor piercing evasion and usually you can make him dismount in records mode and go yolo against their frontline his high melee evasion will help him survive and cut down those ji infantry.
The yellow one (commander charisma or official authority) meh only the best to use saber cav rush toward their archers.
Green and red (guardman and warrior build) should be your main core army as green make spearman useful and the increase in bodyguard make him versatile
Red can be player as DPS cav just do like Lu Bu stack 3 cav in the retinue at least rear attack them to doom, Shocktrooper warband require no need for long range.

Long range artillery if they are at the back.
center sword infantry
right and left spearman
archer skirmish mode in front of sword in loose formation if possible
target order for long range spear cavalry>heroes>spear infantry without shield>archers>sword infantry>cav with shield

Order of engagement : if defensive battle in the open put your units in the forest ambush them if they have that get out of the forest as it can burn. If you have that make that forest burn their soldiers.
Offensive battle split your army in 3 blocks mentally or with ctrl +1, 2, 3
Focus on routing their unit one white flag flashing use cav on them and stop attacking once they have the permanant white flag use your cavalry at the rear of another formation.

Ambush battle : in attack you need to kill the half far from the exit pincer attack.
The best bait for AI like player is making a small general stack in their attacking path in the open
The full stack need to be in ambush stance in the forest at reinforcement range and also in front of the bait. in order to zoc a standard battle if it fail.

In defense : you need to run away as fast as you can with the maximum amount of unit if you feel lucky concentrate your forces against one side of the ambush and pray that they rout before you.

City battle : autoresolve work
The other choice starve them if you have numeric autoresolve (time consuming but less loss also good bait for armies too for ambush work greatly as they are often on the march order and will be tired for better ambush battle result)

Defending cities : you need to have garrison building asap in order to hold against attacker if not just auto resolve lose no time to waste battling will often be worse than autosolving.

City size bring wall. Wall is good but often there are some hole on it and make it unreliable. Also unit inherit the warhammer total war magic hook or stair whatever and mean remove your archer from the wall once they are too close put your swordsman/spear on it
Put your barricade and archer on it make infantry at 90 degree of the archer unit so archer have direct fire on their flank unshielded like rome 2 attacker would get wrecked.

Battle example : https://drive.google.com/file/d/1MCtONl_j-dMiXVH4-azm9pK4biWS9F2Z/view?usp=sharing 1vs2 it's a replay file link of an open battle.