Severing relationship with father even though he has financial authority over me? (advice needed)

I am 21 years old and just graduated from college. Long story short, my dad, while he loves me, is extremely controlling, condescending and emotionally manipulative. He completely changed 4 years 以前 after moving in with my stepmom (and is in denial about it), and every time I 或者 someone else has tried to talk to him, he gets furious, 或者 just devalues what we say and nothing changes. He has had financial authority over me all this time, and any time I say 或者 do something that displeases him in the slightest (things that wouldn't even matter to a normal person), he goes ballistic and threatens to cut off all my funding, and takes me on guilt trips and makes me feel like a terrible person ("Do 你 have any idea how hard I work to provide for 你 all? This is the thanks I get for all I've done for you?" etc). My anxiety levels have been killing me because of him. He puts ridiculous rules in place like forcing me to call every night since I live in a different city otherwise he shuts my phone off, I have to get permission to do certain things despite being an adult, etc.
All this time I've just had to go along with it in order to survive and not end up on the streets. However, now that I've graduated, he has less control over my finances. I can afford housing and basic bills with the job I have, and if I had to pay my phone bill I could manage. He's mad at me once again right now because I went to my hometown to pick things up from my mom's house without his permission, and I'm at the point where I literally can't take it anymore and want to just call him and end the relationship. However, I know that in doing so I'll also have to find my own health insurance and I'm worried I won't get approved for anything 或者 be able to afford it. I'm also worried that he might somehow have authority over something else that I'm not aware of.
Even if all goes okay in practical terms and if I don't have much to lose, he still has a way of making people terrified of him and in seemin