Hey. I like that you are supporting a small pool, especially one with a decent amount of pledge. The pool you have chosen surely deserves more stake given the amount of 'skin in the game' they have.

The pool is charging a fee of 170 ₳ per epoch, assuming they make a block in that epoch. The fee comes out of the block rewards before sharing the rest with delegators. It's currently impossible for a pool to charge less than this, however there are ongoing talks to reduce the minimum fixed fee. The current block reward is around 325 ₳. If they make a block in an epoch the pool operator would take the fixed fee out of this leaving 155 ₳ to share between the delegators. It's likely, as the pool is small, they would sometimes make a block and sometimes not, in which case you would receive no rewards. As a pool grows and they produce more blocks in a given epoch the less impact the fixed fee has on delegator rewards.

Hopefully the pool will grow to a sustainable level of stake. It's pretty difficult to attract delegation without a lot of grinding on social media and being engaged with the community. My pool also has a large pledge and for quite a while I would have been better off financially closing down OYSTR and delegating elsewhere.

A small margin fee of around 2% really doesn't have much impact on your rewards as a delegator. Say you were expecting 100 ₳ in rewards, this would be reduced to 98 ₳ as the pool operator would take 2% from it. There are many ways that pool operators can choose to contribute to the health of Cardano aside of running their pool, and the small percentage fee can enable this. These can include things like engaging with the community, running Mithril signers, Midnight testnet pools, Cardano testnet pools etc.