Hey there, and welcome to Apple Support Communities, aikosohma31!
From our understanding, you recently turned on automatic updates for apps but, some of the apps are not updating on their own. We can certainly understand your concern and can help provide some insight.
To start, it’s possible that the updates can not download because of a restriction on cellular data. If you’re running iOS 14 or up, you can go to Settings > App Store. From there, click on “App Downloads” under the Cellular Data section. If this is set to “Ask if over 200 MB”, it’s possible you missed the notification when it first tried to update.
Also, if the update was released while you had automatic updated turned off, it didn’t automatically complete the update once it was turned on. If so, you may need to update the apps manually this time.
We hope you have a great day.