Propose using transaction type 2(EIP-1559) to submit checkpoint

Currently all validators use transaction type 0 to submit checkpoint on ETH chain which has two drabacks:

  1. Slow if gas price increases. Suppose you submit transaction with 100Gwei, then gas price increases to 200Gwei and continue for one hour, you have to wait for one hour for the confirmation of the transaction.
  2. Waste gas fee. Suppose you submit transaction with 100Gwei, then gas price decreases to 50Gwei, you only need to pay about 50Gwei if you use type 2 transaction instead of 100Gwei with type 0 transaction.

You will help Polygon community by accelerating submitting checkpoint and this can also save you gas fee.

Here is the guide to send type 2 transaction. And make sure to set maxFeePerGas at an approriate level such as 500Gwei so our transactions can also pass quickly when ETH network is congested. You only need to pay about 50Gwei if base fee is 50Gwei, if base fee is 400Gwei, you will pay about 400Gwei.