There is no limit on how much PAYD you can stake into the rewards pool. When you stake PAYD into the rewards pool, you immediately start earning a proportion of the ETH2.0 validator and mining rewards, and the liquidation rewards on the platform.
From Cache: When users Stake ETH into the Cache, they issue PAYD. The issued PAYD can be directed towards the wallet or to the rewards pool.
Direct Stake: Users who have PAYD in their wallets, can stake PAYD directly via manage rewards.
Users can unstake any amount of PAYD from the Rewards Pool to their wallet at any time. The rewards are paid out per proportion of PAYD staked relative to the entire pool, and will be recalculated every time a reward is paid out. Thus, when the balance of PAYD is changed, the user will also earn less or none of the rewards from that point.