Hi Alexlmao_,
Thank you for posting in Apple Support Communities! Is this happen with a specific social media app or multiple? Are there any updates available for those apps? You can go to the App Store, and tap on your profile picture in the top the screen. Scroll to see any pending updates and tap update to install them.
How to manually update apps on your Apple device
You mentioned that your cellular data was enabled, is it enabled for those specific apps as well? You can confirm by going to Settings > Cellular. If you scroll down, you can see a list of all app and confirm that cellular data is enabled for them.
Use cellular data on your iPhone or iPad
Are there any iOS updated that need to be installed for your iPhone 12? You can confirm by going to Settings > General > Software Updates.
Update your iPhone, iPad, or iPod touch
Be sure to back up your data before installing any updates. If you use iCloud to back up, you can initiate it by going to Settings > Your Name > iCloud > iCloud Back up and tap back up now.
You can find additional back up methods here: How to back up your iPhone, iPad, and iPod touch.
Have a good one!