Making this creaking noise while accelerating?

Hello,

It does sounds like the U joint making that noise.
As you can hear it when the shaft is under load and the noise goes away when in neutral.
To check the U joint remove the driveshaft and move the U joint in all direction look for hard spots or too much play.
You will also see a rust colored powder if the U joint has failed and needs replacement.
This is due to metal on metal contact without any lubrication. That also creates noise.

Here are couple of helpful articles:

https://www.2carpros.com/articles/how-u-joints-work

https://www.2carpros.com/articles/how-to-remove-a-drive-shaft

Please let me know of any questions.
Thank you.