Your iPad has gone into restore mode.
If no data backups to Apple iCloud, or to a full computer or to any other data “cloud”, online, offsite data storage or backup services OR any other prior backups, then the data stored on this iPad is already gone forever.
Sorry.
You will need the use of a Mac or Windows PC to restore this device, now.
Tap the link below.
Restore your iPhone, iPad, or iPod to factory settings - Apple Support
Make sure your iPad is, at least, charged to 50% or greater to attempt this.
If NO access to a Mac or Windows computer, you will have to seek help from a good friend or family member, with a full Mac or Windows PC, to help you out
OR
Search online to locate and call contact your nearest, “local” Apple Store location to try/attempt to make an appointment to get your Apple iPad upgraded/updated to its latest iPadOS 15 version.
Apple Store employees will be glad to help/assist you.
Best of Luck to You!