I recently took this so I can include my 5¢.
For the first section I didn’t have trouble with most of the test, but for the Ocean21 parts I was unable to distinguish the white from the light sky blue. The two practice tests made that obvious to me, both looked white. I took the test in a dark room with a clear monitor, so it was me, not my setup. I’m certain I got all the ocean 21 white and sky blue questions wrong, but I still scored above the 90% cutoff. This section also took the longest for me. There were two practice tests with like 20 examples each. The actual test had around 60 if I remember correctly. So maybe 4 of those were ocean21 white/sky blue questions.
For the Alert Detection, it is well described here. What I would add is that the alert is blinking, not just a solid color, which makes it much easier to find. However there will often be up to 1 other text blinking on the screen that does not include the CA. My advice would be to lean more on your ability to detect movement through your peripheral vision and check the movement for the red CA. You can test that strategy out during the practice test. There were over 220 of these on the actual test so like another commenter said, take advantage maybe 5-10 of the 30 seconds provided to answer to not go crazy and overwhelmed.
Weather detection is simple, there were maybe 30 total questions on the real test.
The Restricted Airspace was also simple, there were only 2 questions.
The bulk of the time spent is on the first 2 of the 4 sections. I got worried that I was going to miss my flight (which I almost did) but the last two sections went real fast.
I took my time. The proctor was very friendly and helpful, spent their time in their office while I took it around the corner, so it wasn’t like they were looking over my shoulder the whole time or making me feel pressured to do it quickly.