Minecraft Legends

I'm not sure what was wrong with the campaign method, but I couldn't send more than 68 troops, even with 100 available.

Here's versus mode method I used:
•Host a private solo versus match
•collect wood and stone, build 3 arrow towers to defend each base
•kill piglin and collect lapis
•Get a cobble Golem army, farm the piglin buildings for prismarine
•Build 2 Improvement Hubs, put 2 Flames of Creation in one Hub, fill the other with Banners. You need atleast 7 Banners.
•Build 80 Cobble Golems, press X until all 80 Golems are in army, hold RT then hold B or Y.

This is technically unlockable by building 4 of the "Imporvement: Banner" structures (Cost 100 stone, 100 Prismatic shards, and 25 gold each). These will increase your commandable unit cap by 15 each. You start at 25, so building 4 will increase your cap to 85.

If this is all that you wish to do, simply herd troops throughout the world and then once at 80, give a command.
What you can also do is increase your flame count by building flames of creation in order to increase your max amount of flames (Summonable troops) to reduce the amount of troops you may have to find out in the wild in order to finish this achievement.

A quicker and easier way to do this is do the Is to do the lost legends from the main menu, you dont have to build any banner upgrades or flame upgrades all you have to do is defend the base until about level 14 thats when I got it. After every level that you survive your flame increases aswell as how many mobs you can command.

You can do this more easily in Custom Versus Mode. I did this with a friend on opposite teams and we both unlocked the achievement together.

Give yourself loads of extra resources and start the game. Make two Improvement Hubs and fill them with Banners.

Create a Stone Golem Spawner and create 100 Golems. Head to the nearest Piglin Camp and send them to attack. Hold RT and Press Y on a Piglin building.