This works for Standard kills and tasks as of December 2024, but does not work for hide and seek mode.
**Credit to CookiestMonsterr: https://www.playstationtrophies.org/game/among-us/trophy/415544-scourge.html

Step 1. Connect to online match
- Ensure to wait until the match has started and you can move around in the active match (backing out of the lobby will not work)

Step 2. Once the match has started, unplug/disconnect your internet connection

Step 3. Try to move around in the online match, until the game kicks you to the main menu for connection lost

Step 4. Keep your internet disconnected, and start Practice mode. I would recommend Mira HQ (easiest task map)

Step 5. Once in practice mode, reconnect your internet. You must have an active connection for achievement tracking, but do not reconnect until after practice mode has started and you can move around.

Step 6. Farm kills as impostor in practice mode (can kill 1 of 6 bots around the map every 15 seconds. The 6 bots will respawn after all have been killed)

Step 7. Farm tasks as crewmate in practice mode. Cafeteria on Mira HQ is easiest (one task every 6 seconds): choose the vacuum vent task directly above the laptop, then go to the laptop after completing the task to reset the vacuum task and repeat.
The standard kill/task process will take a few hours to complete. Good luck and happy farming!