Howdy Sk_Fish_Whisperer,
Thanks for posting in the Apple Support Communities.
It sounds like you're looking to use a YouTube feature with your iPhone to watch VR videos, right?
If we have this correctly, be sure you have the latest app update installed if you were previously able to do this with your iPhone. For assistance with updating apps on your iPhone, check out the steps below. You can find additional steps for other devices, here: How to manually update apps on your Apple device - Apple Support
How to manually update apps on your iPhone or iPad
1. Open the App Store.
2. Tap your profile icon at the top of the screen.
3. Scroll to see pending updates and release notes. Tap Update next to an app to update only that app, or tap Update All.
Learn what to do if you can't update an app on your iPhone or iPad
If that doesn't help, this feature may not be available on iPhone according to the following resource we found from YouTube Help. Should you need additional assistance, we'd recommend working with them:
YouTube VR system requirements & availability - YouTube Help