iPad 6th Generation is USELESS with new iOS update. What to do?

My 6th Gen iPad (wifi) has become useless since I updated it to 17.3.1

It literally takes up to 30 seconds to load an app, the app crashes often. This is happening with all apps, including apple's own apps: Books, Netflix, Reddit. It even takes 10 seconds to load up settings.

I think I was on 16.6.1 and it worked great. I just got tired of all the notices to upgrade the iOS and went ahead and did it. BIG MISTAKE.

What can I do to restore this back to a useable device?