I'm looking for information on the difficulty of this course, especially compared to it's first semester counterpart 20A3. Thank you!

It's easier than the first orgo.

There are fewer reactions that you need to know. And there are only three reaction types that you really need to understand, everything else is a modification of these three reactions.

You would still have to know all the reactions from 2OA3 right?

Eh, i forgot most of them because I took 2OA3 in the summer.

They usually do quick reviews in class and those were sufficient to do well. They didn't focus a lot on 2OA3 reactions, imo.