Hi! i would suggest to give Rewards for higher levels.
i mean: when you reach level 1000 you gain trusted player stats and on level 2000,3000,etc. you don't gain rewards or unlock a new thing you can do.
on level 2000: you can now get a FlameThrower weapon with the /gmg cmd
on level 3000: you get 200K extra money (automatically send to bank account)
on level 4000: you get 500K extra money (automatically send to bank account)
on level 5000: you get 700K extra money (automatically send to bank account)
on level 6000: you get 1M extra money (automatically send to bank account)

after reaching levels after 6000 (7000,8000,etc.) you don't get rewards just continue the gameplay normally.

Hope you like my idea.
Thanks For Your Support.
Regards:
@Abdullah