With Stader Labs, the amount of MaticX you hold doesn’t change to reflect rewards. Rather, the amount of MATIC you can withdraw in exchange for your MaticX updates according to a conversion rate where your MaticX represents your proportional claim to MATIC on the Stader Labs protocol. This conversion rate increases or decreases based on the performance of the protocol to reflect any rewards you may receive. Stader Labs typically updates the conversion rate daily.
For example, if you initially received 1 MaticX when Stader Labs' conversion rate was “1 MaticX = 1.1 MATIC” and your share of MaticX on Stader Labs gets you 0.1 MATIC in rewards over time, the conversion rate would be expected to update to “1 MaticX = 1.2 MATIC”.
If you want to skip the manual calculations, you can easily check the amount of your rewards in the Stake section of MetaMask Portfolio, under the ‘Lifetime Rewards’ column.
If you want to withdraw or swap to exit your staking position, see our article for information.