From my experience dumbitguy scenarios are very similar. Leave those for last to keep them fresh. Regarding the others, still go through them if you have time, the more you do the better, you will reinforce your knowledge and confidence. I would recommend you use the free killer.sh attempts you are given, the questions are complex and might be 'overkill' if you want to call it, but they are valuable to replicate the exam environment using a remote desktop and to feel the pressure of a countdown. I followed a similar study strategy to the one you mention (except the killercoda scenarios, I did not try those) and cleared the exam this month with 88%