FWIW, we visited Universal last year (staying onsite there) for all of President's Day week, arriving right on Monday (President's Day). Although the crowds were heaviest on that arrival day and diminished every day for the rest of the week, even at their worst, they really weren't bad at all. I'd read ahead of time that Universal is much less affected by seasonal vacation crowds than Disney World is, and in my experience (visiting Universal the previous year on a low-crowd random week in May, and again over February break), that was true.
For the best Universal crowds, avoid the previous Friday (which will also be Valentine's Day this year) through President's Day Monday (2/14-17, 2020), and of course, arrive just before rope drop and head straight to Harry Potter and/or the big coasters if you're planning on doing those attractions in standby. If you're planning on purchasing the Express Pass or Unlimited Express Pass add-ons, then you don't even need to worry about what day you visit or what order to hit attractions in, because crowd levels won't impact your wait times appreciably at all.