I cannot pair my 4th generation Apple TV with the new Siri Remote. It is still paired with 1st generation siri remote

Here are the steps to Pair your new Siri remote.

How do I pair a new Siri Remote with my existing Apple TV?

Note as of 6-5-21 latest tvOS is 14.6

From New Apple Siri Remote 2021 Owner’s Thread + FAQs + User Guides + News.

You need to unlink the old remote first.

1. Unlink your Apple Remote to your Apple TV. On your Apple Remote, hold down Menu and Left for six seconds. Then on your Apple TV, look for  above an icon of a remote.

Glad to hear you got thee new Siri remote paired and working. 😊