Before attempting to modify the gas fee of your transaction, please keep these things in mind:
Gas Price is the amount of RON you're willing to pay for each unit of gas.
1 GWEI = 0.000021 RON
Gas Limit (Cannot be changed)
Gas Limit is the maximum units of gas you're willing to spend.
Gas fees are payments made by users to compensate the node validators for the computing energy required to process and validate transactions on the Ronin blockchain.
Editing the Gas Fee of your Transaction
To manually edit the gas fee, you will need to click "ADVANCED".
Make sure that "Pay with RON" is selected then click EDIT PRIORITY.
You will now be able to modify the gas price (GWEI). You will be able to see the estimated transaction fee below. Once you are done, click Confirm.
Make sure that you know how this works before attempting to modify the gas price or else the transaction may fail or the gas fee would be too high.
If you modified the value in either Gas Price and did it correctly, the value shown in Transaction Fee should have changed. Make sure to check it before confirming the transaction.