Foundry default sender when deploying

Question

I'm using scaffold-eth2 with foundry as a base framework but when trying to deploy I am getting this error:

You seem to be using Foundry's default sender. Be sure to set your own --sender. No associated wallet for addresses: {0x1804c8ab1f12e6bbf3894d4083f33e07309d1f38}. Unlocked wallets: [0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266]

I know I can specify the deployer in the CLI with a flag but I'm worried it will mess up the rest of the interactions with scaffold. Currently I'm using scaffold's yarn deploy which is defined as forge build --build-info --build-info-path out/build-info/ && forge script script/Deploy.s.sol --rpc-url ${1:-default_network} --broadcast --legacy && node script/generateTsAbis.js

I've put my deploy file here:

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import "../contracts/TrailMixV2.sol";
import "./DeployHelpers.s.sol";
import {HelperConfig} from "./HelperConfig.s.sol";

contract DeployScript is ScaffoldETHDeploy {
    error InvalidPrivateKey(string);
    address public constant USER = address(1);

    function run() external {
        uint256 deployerPrivateKey = setupLocalhostEnv();

        if (deployerPrivateKey == 0) {
            revert InvalidPrivateKey(
                "You don't have a deployer account. Make sure you have set DEPLOYER_PRIVATE_KEY in .env or use `yarn generate` to generate a new random account"
            );
        }

        HelperConfig helperConfig = new HelperConfig();
        (
            address erc20Token,
            address stablecoin,
            address router,
            address priceFeed
        ) = helperConfig.activeNetworkConfig();

        vm.startBroadcast(deployerPrivateKey);
        TrailMix yourContract = new TrailMix(
            USER, // owner
            erc20Token,
            stablecoin,
            router,
            priceFeed,
            10 //trail percent
        );
        console.logString(
            string.concat(
                "YourContract deployed at: ",
                vm.toString(address(yourContract))
            )
        );
        vm.stopBroadcast();

        /**
         * This function generates the file containing the contracts Abi definitions.
         * These definitions are used to derive the types needed in the custom scaffold-eth hooks, for example.
         * This function should be called last.
         */
        exportDeployments();
    }

    function test() public {}
}