The Ethereum got changed. To pay $2 you need to spend $10 on fee.
If you use the same wallet for all your nodes (as per Node Operator Terms & Conditions), they would accumulate all payouts and can clear the threshold.
The threshold is calculated very easy - take 4 times of avg transfer fee for ERC20 from there (it’s calculated for each payout): 15 Gwei | Ethereum Gas Tracker | Etherscan
Doesn’t seems right. Please, check your dashboards and take a look on how much undistributed payout do you have.
The minimum payout threshold in June 2021 for all previous periods was around $10: June 4, 2021: Payouts for the month of May are complete
Of course you will not reach a threshold if you used a separate wallet for each your node.
You always can opt-in for zkSync and receive your payout independently of Minimum Payout Threshold on Ethereum.