Welcome Draa716,
It appears that you're unable to adjust Auto-Lock on your iPad. We'd like to verify your settings and provide you with some steps that may help you resolve this issue:
• Restart your iPad
• Is Low-Power Mode enabled?
To turn Low Power Mode on or off, go to Settings > Battery. You can also turn Low Power Mode on and off from Control Center. Go to Settings > Control Center > Customize Controls, then select Low Power Mode to add it to Control Center.
Click here for more details: Use Low Power Mode to save battery life on your iPhone or iPad
• Verify if there are any parental control settings that preventing you from increasing the time limit: Use parental controls on your child's iPhone, iPad, and iPod touch
• Check to see if you have any profiles installed on your iPad: How to delete an app that has a configuration profile on your iPhone, iPad, or iPod touch
We hope this helps. Stay safe and well!