The dome, wall, barrier whatever you want to call it is there is protect us and keep us inside. According to the Bible, God who created this enclosed system. Doesn't want us go outside of it or escape. Which makes sense on a creators viewpoint since we are here according to the bible as simply a test to experience good and evil.

When the test is done. If your soul passes the test. You get to go to Gods world or another test.

The bible clearly defines how our world is in simple terms. It doesn't really go into technicalities like what's beyond the wall, or what it's made from or how to get through it.

You don't need to overthink it. Don't think about what's outside our world. Just inside.