How do I send Spl tokens to other wallet consistently?

Question

I'm new to solana development but I'm facing an issue. I'm writing a function to send spl tokens to other wallets using the private keys. I'm coding in Javascript. The issue I've been facing is that it goes sometimes but doesn't most times. I tried increasing priority fee like this (Hope I'm doing it right. Solana's docs are down, including this)

I get this error whenever it fails. After taking a long time, it returns

Error occurred: TransactionExpiredBlockheightExceededError: Signature 2FbKMGHSrcrV1xxxxxxxxxxxxxxxxxxxxx has expired: block height exceeded.
at Connection.confirmTransactionUsingBlockHeightExceedanceStrategy

Here is my code

const sendSplTokenWithBase58 = async (
    privateKeyBase58: string,
    toKeyBase58: string,
    numOfToken: number,
    tokenAddress: string,
    priorityRateMicroLamports: number = 25000, // New parameter for the priority rate in microLamports
) => {
    try {
        const splToken = await import("@solana/spl-token");
        const solana = await import("@solana/web3.js");

        const privateKey = Buffer.from(bs58.decode(privateKeyBase58));

        const fromKeyPair = solana.Keypair.fromSecretKey(privateKey);
        const mintAddress = new solana.PublicKey(tokenAddress);

        const tokenAccount = await splToken.getOrCreateAssociatedTokenAccount(
            connection,
            fromKeyPair,
            mintAddress,
            fromKeyPair.publicKey,
        );
        console.log("1");
        const destinationAccount = await splToken.getOrCreateAssociatedTokenAccount(
            connection,
            fromKeyPair,
            mintAddress,
            new solana.PublicKey(toKeyBase58),
        );
        console.log("2");
        // Instruction to set the compute unit price for priority fee
        const priorityFeeInstructions = solana.ComputeBudgetProgram.setComputeUnitPrice({
            microLamports: priorityRateMicroLamports,
        });
        console.log("3");
        // Create a transaction with the priority fee instruction and token transfer instruction
        const transaction = new solana.Transaction().add(
            priorityFeeInstructions, // Add the priority fee instruction
            splToken.createTransferInstruction(
                tokenAccount.address,
                destinationAccount.address,
                fromKeyPair.publicKey,
                numOfToken * Math.pow(10, decimal),
            ),
        );
        console.log("4");

        // const latestBlockHash = await connection.getLatestBlockhash("confirmed");
        // transaction.recentBlockhash = latestBlockHash.blockhash;
        console.log("4.5");
        const signature = await solana.sendAndConfirmTransaction(connection, transaction, [fromKeyPair]);
        const transactionInfo = await connection.getTransaction(signature);
        console.log("5");
        // Extract relevant information from the transaction details
        const transactionHash = signature;
        const transactionStatus = transactionInfo?.meta?.err ? false : true;
        const splTokensSent = numOfToken;

        return { transactionHash, transactionStatus, splTokensSent };
    } catch (error) {
        console.error("Error occurred:", error);
        return { transactionHash: false };
    }
};

It does all the console.logs up till 4.5 and then waits a long time to fail and show that error.

The confusing thing is that I've had a few times it just went through. I'm confused with the inconsistency...