In your test, you actually have more than A and B as you are continuously testing.
B is Winner
B is winner
But in your example, I don't know why you would want to move to the next phase split test without getting results from your previous test. Best practice would be to do what you are doing whereby you complete a test, clone and move on to test the next aspect of your emails. Otherwise, you end up testing multiple pieces at once without knowing what is making the biggest impact.
I do get results before the next phase of testing. I was hoping there was a way that meant I didn’t need to recreate a whole new email each time (even with cloning)
That has to do with email analytics. If you didn't create a whole new email each time, then the stats of the previous email would be attached to the future email which would confuse the testing. If the emails are part of a workflow you could swap in new emails to test if that is more in line with what you are thinking. https://knowledge.hubspot.com/workflows/automate-ab-emails-with-workflows