The change in pre-existing conditions does not apply to those on Medicaid, Medicare, employer insurance, individual insurance, or Obamacare.
It does not apply to people in states that do not seek this waiver, which will be all the populous states, all the blue states and many red states.
In the few states that do seek this waiver, the only change in pre-existing conditions is for that extremely small number who were previously covered by Obamacare; then dropped Obamacare for over 63 days; and then try to re-apply with a newly acquired pre-existing condition.
In other words, it is targeted at an extremely small number of people who intentionally seek to game the system and whom a few states that don’t want to be gamed.