Quizzes with a mixture of CodeRunner and non-CodeRunner questions are a bit tricky. For formative feedback I stick with showing feedback immediately - students are much more motivated, and learn more, if they get instant feedback on their answers. For summative assessment (tests, exams) you need to compromise a bit. You can run the quiz in, say, Deferred Feedback mode but set the Review Options for "During the Attempt" to show feedback but hide correct answer, whether correct and mark. CodeRunner questions always display the Check and Precheck buttons (if enabled) regardless of mode. You need to experiment to find the best mix for your needs. Be warned that some question types (e.g. Cloze) leak information if you navigate away and back again.
Yes, everyone should run their own Jobe servers. I can't provide a compute service for the entire planet :)
Setting up a Jobe server in the cloud, such as on DigitalOcean, takes about 20 minutes and costs as low as $5 per month. See this video. Or if Docker is installed (which even works on Windows) you can run Jobe in a Docker container with just a single command. You can even do that on your Moodle server, though I don't recommend that, for both security and load reasons.