What is the difference between these two key files?

What is the difference between these two key files?

For key1.pem, I am using WSL and OpenSSL. First I generate the an RSA private key used for signing with this exact command:

openssl genrsa -aes256 -out private.key 1024

Then I create a certificate and private key using this command:

openssl req -x509 -nodes -days 365 -newkey rsa:1024 -keyout key1.pem -out cert1.pem -config config.cnf

The config file looks like this:

[req]
default_bits  = 1024
distinguished_name = req_distinguished_name
req_extensions = req_ext
x509_extensions = v3_req
prompt = no
[req_distinguished_name]
countryName = US
stateOrProvinceName = AL
localityName = City
organizationName = Org
commonName = testing.local
[req_ext]
subjectAltName = @alt_names
[v3_req]
subjectAltName = @alt_names
[alt_names]
DNS.1 = testing.local
DNS.2 = testing2.local
IP.1 =  192.168.1.1
IP.2 =  192.168.1.2

When I use this certificate and key on my device, everything works fine. But the problem is I am trying to move to generating these files with Python (pyOpenSSL) and when I use the cert and key files that are generated from my python script, it doesn't work, and I need to know what I'm getting wrong or missing in the Python version. So for key2.pem, this is how it is generated:

    # create a key pair
    private_key = crypto.PKey()
    private_key.generate_key(crypto.TYPE_RSA, RSA_KEY_SIZE)

    # create a self-signed cert
    cert = crypto.X509()
    cert.get_subject().C = data["C"]
    cert.get_subject().ST = data["ST"]
    cert.get_subject().L = data["L"]
    cert.get_subject().O = data["O"]
    cert.get_subject().OU = data["OU"]
    cert.get_subject().CN = data["CN"]
    cert.get_subject().emailAddress = data["emailAddress"]
    cert.add_extensions(
        [
            OpenSSL.crypto.X509Extension(
                b"subjectAltName",
                data["isCritical"],
                b", ".join(data["extensions"])
            )
        ])
    cert.set_serial_number(data["serial"])
    cert.gmtime_adj_notBefore(NOT_BEFORE)
    cert.gmtime_adj_notAfter(NOT_AFTER)
    cert.set_issuer(cert.get_subject())

    cert.set_pubkey(private_key)

    cert.sign(private_key, HASH_ALGO)

    with open(CERT_FILE_NAME, "wt") as f:
        f.write(crypto.dump_certificate(crypto.FILETYPE_PEM, cert).decode("utf-8"))

    with open(PKEY_FILE_NAME, "wt") as f:
        f.write(crypto.dump_privatekey(
            crypto.FILETYPE_PEM, 
            private_key, 
            passphrase=b"pass"
        ).decode("utf-8"))

Do you see anything that the python script is doing differently than the openssl command is?

One difference that I'm not even sure matters is that when I use WSL with OpeSSL, it outputs the private key, then the certificate and key, so I have three files total. When I do the python version, it's only the latter cert and key files. These are the only two files that go onto my device. The formatting/encoding of the key file looks good.