The wiki has a list of every action (Xevyr pretty much covered them) that counts towards the purge meter, along with caveats for what does and does not count.
If you have other things you want to do aside from playing Conan, one thing you might try is this:
- Think of a thrall you really want to acquire, but never is around.
- Set up a camp near to that thrall’s spawn location with a bedroll.
- Set a timer for 15 minutes.
- Every time the timer goes off, place a new foundation not attached to anything else, then pick it back up, then go to the spawn and kill whoever is there (unless it is that thrall you want, then bonk them instead), then pull your bracelet and respawn at your bedroll.
- Reset the timer and go do that other thing you want to do aside from playing Conan.
Spend a few hours doing this, and your purge meter will significantly increase.