There is a ceiling.

Once you reach max. checkpoints, that's all there is.

Remember, you must win your event to collect personal achievements.
- so make sure each member gets at least that amount to maximize their rewards.
- remember, it does not matter how they get those rewards. Some will train, some will study, some will yield. Only the points matter, for reaching checkpoints.
= You will want to balance the players so that you get the necessary points in the categories you need, to actually win the event (and collect the personal rewards.)

You can gain further rewards by your order placing in the top X of all in the kingdoms in the event. Click on the ranking tab to see where you stand. Click on a ranking to see what rewards they will get. Different rankings accomplish different rewards. Largely, if you cannot hit one of the top 3 spots the reward may not be worth the effort. (Better to spend that effort to make sure you reach the checkpoints of the next event.)

https://support-portal.plarium.com/en/throne-web/faq/ratings

Once you reach max. checkpoints, that's all there is.

Nope what?