I have been working in linux systems for many years. Most my experience has been with debian based distro’s until my current position. I have spent about the last year and a half working with Red Hat Enterprise Linux. There are differecnes between distrubtions but for the most part the basics are the same. I devied to get my Red Hat certification(s).
I went throug the Red Hat courses RH124 and RH134. I probalby could have done the single course RH199. The courses I took were well layed out. They offer great instruction and plenty of lab time. The only section on my test I did not feel was covered well enough in the class was containers.
Time magagement is key on the test. There is a ton to acomplish and not alot of time to do it. If you have to lookup every command you will not complete. Know your commands fairly well. They may be some obscurities about switches you may need and a quick scan of the man page can help, but I would not reply on looking everything up. Take your time and have plenty of practice.