Minecraft Legends

This requires to finish campaign with specific settings - gravity value of 60% or less and high jump enabled.
Can be done together with

Let's get straight to the point.
Go to Custom Game and in custom settings do next:
1. World -> Gravity -> Global gravity set to 60% or less, my setting was 50% (for this achievement).
2. World -> Knockback -> Player Knockback - set to 200% or greater, my setting was 250% (for When Pig(lins) Fly achievement)
3. Resources -> Starting Resources - set everything to max or as much as you want, 3k of everything is enough. You can leave Max Resources as is.
4. Player -> Modifiers -> Player Damage - set to 500%
5. Player -> Bonuses - enable everything, most important is Invulnerability!
6. Player Tools -> Tech Tree -> Unlock all - enable
7. Piglins -> Modifiers - set all to minimum 10%
8. Piglins -> Invasion Settings -> Invasion Pacing - set to Slow
9. Piglins -> Invasion Settings -> Invasion Activity Level - set to Low
10. Piglins -> Invasion Settings -> Horde of the Hunt, Bastion, Spore set all bases to 1

Now you can go straight to the bases and attack every building with your sword , except for portals and bosses. In order to destroy portals and kill bosses find nether spreader and destroy it. Now in this place grass appears. Build there creeper spawner. Usually 5-6 creepers are enough to destroy portal. With bosses it's the same, but they take more creepers, around 10-15.

After you destroyed every base and killed every boss you have one final fight with the final boss. It's done the same way. When final cutscene plays you will get two achievements (second one is When Pig(lins) Fly).

I accomplished it in 2.5 hours.

This requires to finish campaign with specific settings - gravity value of 60% or less and high jump enabled.
Can be done together with

Let's get straight to the point.
Go to Custom Game and in custom settings do next:
1. World -> Gravity -> Global gravity set to 60% or less, my setting was 50% (for this achievement).
2. World -> Knockback -> Player Knockback - set to 200% or greater, my setting was 250% (for When Pig(lins) Fly achievement)
3. Resources -> Starting Resources - set everything to max or as much as you want, 3k of everything is enough. You can leave Max Resources as is.
4. Player -> Modifiers -> Player Damage - set to 500%
5. Player -> Bonuses - enable everything, most important is Invulnerability!
6. Player Tools -> Tech Tree -> Unlock all - enable
7. Piglins -> Modifiers - set all to minimum 10%
8. Piglins -> Invasion Settings -> Invasion Pacing - set to Slow
9. Piglins -> Invasion Settings -> Invasion Activity Level - set to Low
10. Piglins -> Invasion Settings -> Horde of the Hunt, Bastion, Spore set all bases to 1

Now you can go straight to the bases and attack every building with your sword , except for portals and bosses. In order to destroy portals and kill bosses find nether spreader and destroy it. Now in this place grass appears. Build there creeper spawner. Usually 5-6 creepers are enough to destroy portal. With bosses it's the same, but they take more creepers, around 10-15.

After you destroyed every base and killed every boss you have one final fight with the final boss. It's done the same way. When final cutscene plays you will get two achievements (second one is When Pig(lins) Fly).

I accomplished it in 2.5 hours.