How to verify that a ERC20 transaction has not been altered

[skolliecool]

Hi all

So I am sending USDT, and to do that, I send it using the contract.transfer method (after loading the transfer ABI into the contract meta-class). I am doing this in the browser like so:

const contractAbiFragment = [
  // Some details about the token
  "function name() view returns (string)",
  "function symbol() view returns (string)",

  // Get the account balance
  "function balanceOf(address) view returns (uint)",

  // Send some of your tokens to someone else
  "function transfer(address to, uint amount)",
]
const contractAddress =  "0xdAC17F958D2ee523a2206206994597C13D831ec7"; // USDT contract
const signer = ...; // The metamask signer
const contract = new ethers.Contract(contractAddress, contractAbiFragment, signer);
const tx = await contract.transfer(strategyWalletAddress, numberOfTokens);

The result I get is this:

{
  "hash": "0xf4584008cc70f2f532765a2f035a2525992a258b2d2afd6b49ad5b2857a6197d",
  "type": 2,
  "accessList": null,
  "blockHash": null,
  "blockNumber": null,
  "transactionIndex": null,
  "confirmations": 0,
  "from": "0x0936c90c59ecb79fc01C780f283CABfB9e118940",
  "gasPrice": {
    "_hex": "0x203f403384",
    "_isBigNumber": true
  },
  "gasLimit": {
    "_hex": "0xb41d",
    "_isBigNumber": true
  },
  "to": "0xdAC17F958D2ee523a2206206994597C13D831ec7",
  "value": {
    "_hex": "0x00",
    "_isBigNumber": true
  },
  "nonce": 38,
  "data": "0xa9059cbb0000000000000000000000009418bfc542817e4320480990f34951351b0db5130000000000000000000000000000000000000000000000000000000002faf080",
  "r": "0x270e826d5bbf71fa492de0da460b06f0f586d007d05db364493d1bf70b4fc77e",
  "s": "0x4b4795d7c50cd4e56342ab3044cb3986f85278a4a2377dcc621589d8289bfaaf",
  "v": 1,
  "creates": null,
  "chainId": 0
}

Now what I want to do is send this transaction to the server, where the server will verify it. I am not interested in having it confirmed by blockchain, all I want to do is verify that the transaction has not changed.

Here are my questions:

1. Has this transaction been signed?
2. On the server, I would want to use utils.parseTransaction, only I would need to serialize the above transaction. This is a problem because when I try to serialize the above transaction, I get Error: mismatch EIP-1559 gasPrice != maxFeePerGas...
3. Most important question: How can I verify that the above transaction has not been altered on the server, without pinging an external provider (so what I would like to do is verify using a signature - I am sure if that is present in the r,s,v variables)

Thanks