optimizing video seems to be stuck.

First, try power-cycling / rebooting the box.

Hey there user_wux1yy. Sorry to hear your new Xfinity box is being a bit stingy with the inital set up, but we defintiely appreciate you taking the time to reach out here in our community, and are here to help! 
I also want to thank our Expert @EG for providing the inital assiatnce they did and for moving your post to the proper area for assiatnce.
If your Xfinity box is still stuck on "Optimizing video," it may be due to HDMI configuration issues. To resolve this, you can try following these steps:

1. Unplug the Xfinity TV Box from the electrical outlet, wait 10 seconds, and plug it back in to restart.

2. Ensure the box is connected directly to an HDCP-compatible HDTV using an HDMI cable, avoiding any adapters or connection accessories.

3. If the issue persists, try using a different HDMI cable.

These steps should typically help in resolving the problem. Please give them a try and if it persists, we're here to dig deeper for you.

It's my pleasure @XfinitySeth ! And welcome aboard !