Hello Spudson,
Thanks for choosing the Apple Support Communities. If we understand correctly, you are unable to use cellular data on your Apple Watch without restarting when it is away from your iPhone. We can understand why you'd reach out for a solution.
First, let's try following this user guide.
Use Apple Watch with a cellular network
If that doesn't help, let's try force restarting your Apple Watch, and test again.
Restart your Apple Watch
"Force restart your Apple Watch
You should force restart your Apple Watch as a last resort and only if it's not responding.
Don’t force restart your Apple Watch if you're updating watchOS. After you see the Apple logo and progress wheel, leave your watch alone and on its charger until the update finishes.
To force restart your Apple Watch, press and hold both the side button and Digital Crown for at least 10 seconds, then release both buttons when you see the Apple logo."
Cheers!