Health care problem, buying private ins in NJ. Shortfall of ACA

I am googling and googling. It seems that you can’t buy ANY insurance after the deadline? Every site says the deadline passed and if you don’t have a qualifying event you can’t sign up. Dropping off the parents plan is not qualified event. Is it true that a person can’t just call up Horizon or Cigna and say they want to sign up? I see short term insurance mentioned, but the sites I tried don’t offer it in our area. (NJ).