I’m tryin to update the latest version an it keeps saying failed to update cause I’m not connected to wifi but I am

Hello ~ Give these steps a try as sometimes this may have if older iOS tried to download but never installed.

1. Go to Settings * General * iPhone Storage
2. Wait for apps to populate below
3. Look for an iOS update* select it and delete it
4. Go to Settings * General |*Software Update
5. Download and install the update

Also take a look here just to be sure:

iPhone, iPad, or iPod touch won't connect to a Wi-Fi network

~Katana-San~

To update all of these requirements must be met:

• You must be connected to a Wi-Fi network (and not a personal hotspot)
• The phone must be charged to at least 50%, and preferably plugged in so it stays above 50% during the update
• The phone must not be in Low Power Mode
• The phone must not be connected through VPN
• The phone cannot be in Airplane mode