It looks like it will be tricky to remove savepoints without first reimplementing operations that involve catching and ignoring certain constraint violations.   For SQLite, that involves DM-17419, and for Oracle, it involves using MERGE, I believe.

I've decided that while this ticket is a good description of a problem, it doesn't reflect how we'll likely address that problem.  I'm zeroing the story points and blocking it on DM-21768, which will probably take care of it (if not, DM-21770 will).  We can then just mark this ticket as done when its blocker is.