How do they compare to each other? How do they compare to the actual test?
If I’m getting ~80% on UpperMark Q-bank, should that be sufficient to pass?
I think you should be good. I used uppermark for my caia level 1 and I thought their questions prepped me well for the exam. Also, I passed with above average in most sections.
In general they both will prepare you for the exam as long as you read them well. Spending enough time on the sections you are not familiar is the key. I’ve used both for different levels. However please know that you WILL get surprise questions on the exam.