I already tried aes-ecb-js and now im trying cryptoJS if it can solve my problem. I already read a few topics and googled a lot but I am not able to decrypt a HEX String with AES ECB 256.
When using an online decoder it works just fine:

I tried with the following code according to the documentation (https://cryptojs.gitbook.io/docs/#ciphers)
console.log('decrypt: ' + result)
const dec = CryptoJS.AES.decrypt(result, key)
console.log(dec)
console.log(CryptoJS.enc.Utf8.stringify(dec))
"key" in this case is a String which looks similar to this: 34AKDASFA12312ADSFKLSDK2
The output is sadly undefined when trying to stringily the word array in var "dec"