Racing on twitch with Beyond Chaos

To be honest, the Speedcave mode could easily take significantly longer than four hours with all flags on. It was primarily balanced for vanilla flags, not chaos flags. It's highly variable though, and there are resources available to make it easier. The main things you would be looking for are Exp. Egg, the Lv-1 esper boost, the Lv+50% esper boost, and possibly the secret item. These are all things that would accelerate the grinding you need to do to survive the bosses at the end of the cave.