JWKS to PEM in bash

jwks-to-pem.sh

#!/usr/bin/env sh
set -euo pipefail

JWKS_TEMP=$(mktemp)
JWKS_URL=$1
curl -s "${JWKS_URL}" | \
    python -c 'import sys, json; data=json.load(sys.stdin); print(data["keys"][0]["n"] + data["keys"][0]["e"])' > "${JWKS_TEMP}"

{
  echo 'MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA' | openssl base64 -d;
  head -c 256 "${JWKS_TEMP}";
  printf '\2\3';
  tail -c+258 "${JWKS_TEMP}" | head -c 3
} | openssl pkey -inform der -outform pem -pubin

doesn't work for me
i got different result then here https://8gwifi.org/jwkconvertfunctions.jsp