Sourdough bread crust will not rip open
I believe that the top element in your pizza oven is your biggest problem. It is broiling the top of the crust, cooking it too quickly. You can use it to preheat the oven, but don’t use it when the loaf is in the oven.
The temperature of the oven may be off as well, if it’s running too hot that could make the problem worse.
Although you’re not having blow out problems, the answers to this question may help.
Bread doesn’t split at the score