Do you have to have cellular to text on your apple watch even when your phone is close to you?

As long as your Apple watch is connected to Wi-Fi or your iPhone via Bluetooth, you don't need a cellular Apple Watch to be able to text.

About Bluetooth, Wi-Fi, and cellular on your Apple Watch - Apple Support

Use your Apple Watch without your iPhone nearby - Apple Support

When you read the "Use your Apple Watch without your iPhone nearby" make sure you read the footnotes. In there you will find that even if you have cellular you still need your iPhone accessible for SMS/MMS messages. Services such as iMessage, WhatsApp, etc... use the Internet and do need the iPhones carrier connection for their messages.