Hi there Jessedebi,
It sounds like your new iPad is displaying a spinning gear unexpectedly when browsing Facebook Marketplace. We're glad you've joined us in Apple Support Communities, and we can provide some guidance.
To start, you'll want to be sure your iPad is running the latest software version, which is iPadOS 14.4. You can check which version it's running by going to Settings > General > About. To learn how to update your iPad, have a look at the support article below:
Update your iPhone, iPad, or iPod touch
Next, you'll want to check the App Store for updates and install any that are available, including Facebook. This link provides instructions for updating your apps:
Update apps or use automatic downloads
If your iPad and all your apps are updated and this behavior persists, try the remaining steps here:
If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open
Afterwards, if your iPad still displays a black screen with a spinning gear, let us know if this only happens when accessing Facebook Marketplace or if you've noticed this happening when using other apps too. We'll take a closer look from there.
Cheers.