The total supply of any cryptocurrency is determined by the protocol that governs its supply. In the case of staking rewards, the total supply can either be fixed or infinite, depending on the protocol. If the protocol provides for a fixed total supply, then the staking rewards will be limited to that amount and no more new tokens can be created. If the protocol provides for an infinite supply, then the staking rewards will be ongoing and new tokens can be created indefinitely. Ultimately, it is up to the protocol developers to decide how many tokens will be created and whether or not the total supply will be fixed or infinite.
