First, nice job on the quant! It's good to know that you have been able to bring your score up there.
I think you're likely right that you partially hurt your verbal by second-guessing / "overtraining" / breaking what had worked for you in the past. My guess is that something else was going on too, though: you probably used a lot of mental energy to get that great quant score, and that would've left less mental energy in the tank for verbal.
In general, yes, there are going to be some too-hard/long questions on verbal, too, not just quant. Someone might not skip as many in their stronger area if that area is super strong (which you are in verbal), but that doesn't mean there won't be times to bail and move on. For a high verbal scorer, it's more likely that you'll be able to eliminate at least some answer choices and then have to guess randomly from among 2 or 3 choices.
I think I can "recycle" some of the earlier MGMAT verbal practice tests
FYI: there's no such thing as an objective "earlier MGMAT test." There's a single database with lots of questions and each test pulls from that database. Within a set of 6 tests, the database is not allowed to pull questions you've seen before. Once you've finished your first set of 6 tests, this "re-sets." Within the second set of 6 tests (now labeled tests 1A, 2A, 3A, and so on), you can see questions that you've seen in any one of the first 6 tests. (But you won't see any repeats within the new set of 6 - ie, test 2A will not repeat any questions from test 1A and so on.)
Okay, so where to go from here? First, this was a real GMAT that you took? Did you order the enhanced score report? The data isn't super-extensive, but it would be useful to know what did actually break down on verbal - did everything drop or just certain question types? That kind of thing.
Next, figure out what was already working for you on verbal and stick with those things. If there are certain weaker areas, fine, you can learn our strategies (or others) for those things - but don't break the processes that were already working for you.
If you get back to your prior performance of 38-40 and maintain your Q46, then you're looking at a 690-700 score. If you can get verbal up to 42, you'll be around 710-720.
In order to hit 40+, you're going to need to have good mental stamina still heading into the verbal portion (which means not blowing too much mental energy earlier - more on this below) and you'll need to have very systematic processes for how you're going to handle every type of question - no skipping steps, getting lazy, making careless mistakes. You can make a couple of careless mistakes at 40+ but too many and your score will drop below that threshold.
So, yes, your focus should be on mixed, timed sets of questions in which you are practicing making all of these decisions and following all of these processes that you decide you're going to use. I would actually do these later in the data, after you've studied some quant, so that you are setting yourself up for the real testing situation (already getting a little tired / sick of this...
Next, there is more quant work to do: your goal is to maintain that score but not need quite as much mental energy to do so. Then, you'll be a bit fresher for verbal and that score will be less likely to drop. So you're going to keep doing what you've been doing on quant with a focus on streamlining - making it easier to do what you already know how to do. (Sure, if there are still things you can learn, go for it - but don't spend so much mental energy trying to improve weaknesses here that you just repeat the same pattern on the next test.)
Put those two things together, and you've got a good shot at breaking that 700 barrier!