Error message on iPad when Safari opened

When I open Safari on my iPad Air (4th Gen) I get the following message: "Application error: a client-side exception has occurred (see browser console for more information)."

This app is set up to use DuckDuckGo Private Browser - I did this years ago before Apple upgraded their own version. Because the browser doesn't allow you to get any further I can't see any way of fixing it. If it's the DuckDuckGo add on I can't turn it off to test it.

What is the "browser console" and where on earth do I find it?? It seems to me there is no way to get the settings page to change the preferred search preference. Or am I missing something?

If the problem lies in software that has corrupted code how do I repair this by reinstalling that Safari app code? Is it possible on an old machine?

Note: before anyone asks this is written on a newer MacBook Pro that doesn't have the problem