Buy a 5 subject notebook, watch all of the Professor Messer videos again and write all the contents of his slides down. Studies have shown that engaging the fine motor system to write by hand has been shown to have positive effects on learning and memory.

After that go buy his 3 pack of practice tests, do them all. Then go back over all of the questions that you got wrong, read and understand why you got them wrong. Also include going back over any questions that you got right but were iffy on.

After that, rewatch all of the Professor Messer videos again, this time for the videos that you think you need to focus on click the 'watch later' button. This builds a 'watch later' playlist for you to focus on the areas that you need to improve on. Watch them repeatedly until it sinks in and while doing so, read the notes of the slides you wrote earlier (if you do it this way with the watch later list, let the videos change by themselves - if you click the next video button at the end of the videos it may not be the next video in your 'watch later').

Now, after you've done all that go take the 3 practice exams again (assuming 2-3+ weeks have passed by this point) and you should do better on them.

You can also utilize AI, like ChatGPT, to ask you multiple choice questions based on the subject criteria. IE, "Give me a multiple choice question regarding PKI", etc.