hi richeze - i hardly get any success with the big4 in the oscp lab, so far i rooted 30 machines in the lab, some people say oscp exam is not much harder but “try harder mantra” is something which keeps bugging me, i am not from the field of pentesting but what i experience here on htb and oscp lab gives me a mixed feeling on exam fail/pass 
anything suggestions on gaining more skills would be helpful - thanks