DNS restricted content on Youtube? Says it's admin, not my account.

I'm just posting as this may be of help.  I had the exact same issue as described.  I'm a system admin by trade so, I was looking to fix this on my own.  However, there is no way to fix this on your own.

T-mobiles' 5G router by default has productivity filtering turned on.  There is not option for you to turn this off yourself.

I called T-mobile technical support.  Let them know the issue, and they turned off this filter for me and resolved my issue.  The typical customer service rep may not be able to help you with this, however technical support should  be able to.

I seem to be a year late as I just purchased the router today.  But hopefully this helps someone in the future.